Handling paths in the MAPDL instance

[germa89]

From #4079 mapdl.directory returns a Pathlib.PurePath object.

Hence you can do the following in PyMAPDL:

>>> log_file = mapdl.directory / f"{mapdl.jobname}.log"
/path/to/mapdl/directory/file.log

The Pathlib.PurePath is aware of the platform MAPDL is running and returns the correspondent Pathlib.PurePath object (PureWindowsPath on Windows OS and PurePosixPath on Linux/Unix systems).

This is quite convenient for managing files when you are connected to a remote instance.