Updates .NET target version to 4.8 (happy to revert this if necessary)
Bumps version number to 7.0.0
Updates nuget dependencies for rhinocommon etc. to v7.0 stable
Modifies the Rhino system directory searcher to look for a Rhino installation that matches the major version of the resolver, i.e. Rhino 7, unless UseLatest is true
UseLatest
istrue