Print error messages to stderr instead of stdout

Closes #86

Closes #88

* adhoc_storage: Add job client information

* adhoc_storage_manager: Now stores adhoc_storage_info records and
  provides functions to update them.

* adhoc_storage_info: New synchronized type keeping updated information
  about the client job assigned to a adhoc_storage instance

* adhoc_storage: The context can now be updated using a new update()
  function (non-synchronized for now, because it is only ever called
  via the adhoc_storage_manager).

* job_info: Type is now synchronized.

* errors: Add ADM_EADHOC_BUSY. Fix missing error messages for ADM_ENOENT
  and ADM_EEXISTS.

* abt/shared_mutex: Is now movable.

scord::job_info is now admire::internal::job_info

Merge branch 'amiranda/82-improve-adhoc_storage_manager-in-scord-to-keep-information-about-registered-instances' into 'main'

Resolve "Improve `adhoc_storage_manager` in `scord` to keep information about registered instances"

Closes #82

See merge request !55

Merge branch 'amiranda/84-new-job_manager-locks-on-std-shared_mutex-instead-of-abt-shared_mutex' into 'main'

Resolve "New job_manager locks on `std::shared_mutex` instead of `abt::shared_mutex`"

Closes #84

See merge request !57

Resolve "JOB ID needed in register_job / register_adhoc_storage"

This MR adds an extra argument `slurm_id` for `ADM_register_job()` since
it is required by !40 in order to deploy an adhoc storage instance.

Closes #83

See merge request !56

Resolve "Add `job_manager` component to scord daemon"

This MR adds a `job_manager` singleton object to the `scord` daemon so that
there's a centralized way of managing the information about jobs registered
in the service. The `job_manager` stores `job_info` objects that allow 
accessing the `job` itself, its `resources` and its `requirements` were they 
needed.

It also updates the `ADM_register_job()`, `ADM_update_job()`, and 
`ADM_remove_job()` rpc handlers and fixes some minor errors with error handling.

Closes #79

See merge request !54

Merge branch 'amiranda/78-there-s-no-way-to-select-the-adhoc-storage-type-when-calling-register_adhoc_storage' into 'main'

Resolve "There's no way to select the adhoc storage type when calling `register_adhoc_storage`"

This MR adds a `type` argument both to `ADM_register_adhoc_storage()` and 
`admire::register_adhoc_storage()` so that client code can properly select
the type of the instance to be registered.

Closes #78

See merge request !53

Resolve "server_id should not be optional in adhoc_storage"

This MR makes the `server_id` member in adhoc_storage explicit. The rationale
is that constructors (for the C++ API) or `.*_create()` functions (for the C API)
will most of the time be called from internal code, since client code will rely
mostly on `ADM_register_.*()` to obtain handlers.

In this scenario, there's no possibility for the `server_id` "to not having been 
assigned yet", which is why it was `optional` in the first place.

Also, this MR renames the `user_id` to `name`, and the `server_id` to `id`.

Closes #74 #75

See merge request !51

Similarly for ADM_storage_create(), admire::storage, admire::adhoc_storage,
and admire::pfs_storage.
Also, rename any references to `server_id` to just `id`.

Resolve "The C++ API should not rely on `unique_ptr`"

This MR removes the need to pass a `std::unique_ptr<admire::storage>` argument 
to `register_adhoc_storage` in the C++ API.

Tests are also updated to reflect this change and to remove dependencies with 
`ADM_storage_create()`, which in the future will become an internal function.

Finally, we fix some use-after-free memory management errors due to 
shortcomings in `managed_ctype`s and the creation function of C API types 
themselves. The errors are "fixed" by not deleting the data, which means that
we are now effectively leaking. So that tests pass, we set `detect_leaks=0` in
`ASAN_OPTIONS`.

Closes #47

See merge request !42

hg_proc_ADM_storage_t: encode/decode server_id

Merge branch 'amiranda/69-adm_register_adhoc_storage-requires-obsolete-adm_job_t-argument' into 'main'

Resolve "`ADM_register_adhoc_storage` requires obsolete `ADM_job_t` argument."

Closes #69

See merge request !50

Resolve "Missing rpc id in log entry for  `ADM_register_adhoc_storage`"

Closes #68

See merge request !49

Resolve "API does not provide facilities to communicate job and adhoc hostnames"

This MR extends the current API by introducing two new structures
`ADM_job_resources_t` and `ADM_adhoc_resources_t`.

- [x] `ADM_adhoc_resources_t` is renamed from `ADM_storage_resources_t` 
and now contains a list of nodes assigned for the adhoc storage instance 
(the PFS is more of a static thing, so it doesn't make sense to have a 
generic interface for this). An `ADM_adhoc_resources_t` argument is added 
to `ADM_adhoc_context_create()` and is propagated through RPCs. This 
allows resource managers (i.e. Slurm or the IC) to inform us about the 
nodes assigned for an `adhoc_storage`.
- [x] A new structure `ADM_job_resources_t` is added to the API, which for 
now contains a list of nodes assigned to a job. An `ADM_job_resources_t` 
argumet is added to `ADM_register_job()` and related functions and is 
propagated to `scord` via RPCs. This allows resource managers to inform 
`scord` about the nodes assigned for a job.

Closes #59

See merge request !43

Merge branch 'amanzano/36-refactor-library-rpc-implementation-of-admire-register_adhoc_storage' into 'main'

Resolve "Refactor library RPC implementation of `admire::register_adhoc_storage`"

This MR moves the implementation of the RPC construction to `admire::detail` in `impl.[ch]pp` similarly to other RPCs already refactored. This includes changing the C ADM_types to native C++ types.

Closes #36

See merge request !26

The previous automatic ID generation caused problems with the usage of
adhoc_storage constructors outside RPC handler code (e.g. during
conversions). It makes more sense for IDs to be assigned by
a server-centric adhoc_storage_manager.