Merge branch 'amiranda/85-adhoc_storage-instances-should-keep-track-of-jobs-using-them' into 'main'

Resolve "adhoc_storage instances should keep track of jobs using them"

This MR associates registered adhoc storage instances with registered jobs.

To do so, it modifies both the `job_manager` and the `adhoc_storage_manager`
classes to store `shared_ptr`s to `admire::internal::job_info` and 
`admire::internal::adhoc_storage_info` records. This allows returning the 
pointers when checking for information as well as modifying the records in
a synchronized manner.

To keep track of adhoc_storage usage, the new internal `adhoc_storage_info` 
type includes a `std::shared_ptr<job_info> m_client` field that models the 
association. As of today, an adhoc storage instance can only have a single
job client associated. Trying to add more will result in error.

Closes #85 #86 #88

See merge request !58