Reworked the build process

[valadas]

The build process was using DNNtc library without referencing any Nuget package.

This PR:

• Re-implements the build process to use Nuke (the build is now a pure C# console application)
• Has a simple click or F5 experience to either deploy or package the module
• Bumps the version to 6.0.0 for next release
• Deletes all local dlls in favor of all Nuget packages
• Bumps minimum DNN dependency to 9.4.0
• Sets up CI build using Github Actions
• Updates release notes and license texts

Closes #55