Rename Location to Project

[ninsbl]

The Python client should follow the nomenclature of the underlying API. See:
actinia-org/actinia-core#565

There might be a need for a transition fase, where URLs with "location" are still supported. However, users could handle this with version-pinning...
Also not sure if there will be a new core API version that could be used to identify if "location" or "project" should be used in the URL...

[mmacata]

It is planned to support both "location" and "project" in actinia-core and actinia-api as long as GRASS GIS supports both - therefore no new core API version so far. With GRASS GIS 9, "location" support can be dropped.