Adding support to ***inq functions

[germa89]

Close #798 by implementing the ``***inq``` functions

Check list:

• Mapdl implementations (console, corba and grpc).
• Mapdl refined grpc implementation
• Documentation. (Pretty much scrapped copied from the MAPDL internals. Therefore, we should probably make sure the info is releasable.
• Test units. They are going to be very small, since they are undocumented and we are not ensuring fully support. I'm just going to make sure the commands run and get an output with valid format.

[akaszynski]

Test units. They are going to be very small, since they are undocumented and we are not ensuring fully support. I'm just going to make sure the commands run and get an output with valid format.

Agreed.

[germa89]

As mentioned before, there are quite a lot of info in the docstrings which I'm not sure if we want to share. Some guidance is appreciated.

Nevertheless, if we are intending PyMAPDL becomes somehow the new way of interact with MAPDL, I see that this documentation is going to be the reference, not only for checking PyMAPDL commands but also MAPDL commands (given the similar syntax and the lack of official public documentation).
Hence I believe we should be ambitious regarding the scope of this documentation and give as much info as possible.

[germa89]

Applying code review.

[akaszynski]

Thanks for incorporating my suggestions. Looks good to me!