Pull RevitNodeTestBase into separate library.

Link to props file to build to correct location. Swap out revit api
paths in proj with correct variables. Change output paths in proj file
to ref output path.
Remove RevitNodeTestBase from RevitNodeTests
Cleanup
Rename library to RevitTestServices
Read DynamoBasePath from config file if found.
Rename directory to match the library.
Duh. Need to relink project after renaming its folder.
Merge pull request #2529 from DynamoDS/MAGN-4776

MAGN-4776 Refactor GeometricRevitTest into separate library