We don't want the log file to be created before command line parsing,
otherwise --version or --help cli option could not work beacause we
don't have permission to write to log file.

Write errors happenig on deamons are now reported back to clients.
"No space left on device" error is now properly propagated to clients.

Port is only meaningful for some of the communication protocols. For
instance psm2 is not using it at all.

Port can be still specified using the --listen,-l flag:

Example:
```
gkfs_daemon --listen "localhost:1234"
```

margo context id is not the id of the host that send the request. Is the
internal context id of local margo instance.

Implement proper error propagation and handling on get_dirents RPC.
Error happening on the deamon are now embedded on the returned response
and the client throws an exception once he receives the response.

Shared-memory communication can be disabled through cmake
compile time option `-DUSE_SHM:BOOL=OFF`

Refactored initialization code.

 - More detailed logging
 - Use exceptions to better propagate errors
 - Log signal type before shutdown

Daemon is now capable of providing version information through the
`--version` cli option.

Get rid of all the occurrences of old project name "adafs" from output
strings and documentation

`adafs_daemon` -> `gkfs_daemon`

get rid of adafs name from folder names

A new cli parameter `--listen`,`-l` allow to specify binding address/interface

RPC port can now be configured at runtime through `--bind-port` command line argument.

For some comunication layers an out of band communication is required for putting in place the specific protocol handshake.

In those case a shared lookup file could be used to distribute deamon's endpoints information to all the clients.

This file need to resides on a shared filesystem and can be specified using the new CLI parameter `--lookup-file`.