* Do not add duplicate solution folders or project directories
* Fix the algorithm for removing empty solution folders
* Improving code by adding description methods. To address PR comments.
* WIP support solution folders for dotnet add and remove
* Add/remove solution folders based on directory hierarchy
* Fix tests
* Disable the solution building tests
* Address PR comments
* Fix a build break due to a new tool version used in the build
* Create SlnProjectExtensions and SlnProjectCollectionExtensions per PR comments