Imported project files modifications check

[IgorFedchenko]

Close #68

The way this is going to work is getting all imported files paths from <Image Project="path/to/props"> tags of all projects in solution, and then checking if any of them were modified.

Will keep PR in draft until add some tests to verify this works well.

[Aaronontheweb]

Sorry about this @IgorFedchenko - looks like I needed to update the Azure DevOps connection. Just did that. If you push 1 more commit that should trigger PR validation.

[IgorFedchenko]

Sure, no problem

[IgorFedchenko]

@Aaronontheweb I could add more tests for multiple imports cases, maybe multiple projects, etc - but there should not be much difference in how the code works in this cases

[IgorFedchenko]

Seems like tests failed, but that is because it thinks that my "SampleProject.csproj" file, generated during tests execution, is a real project. Maybe it should ignore all files under bin directory?

Or, I will just add cleanup code now

[Aaronontheweb]

Thanks @IgorFedchenko! I'll try running this locally and take a look at it. Appreciate the hard work.

[Aaronontheweb]

@IgorFedchenko just validated this on the Akka.NET solution itself, which is where we're going to see this in action first. Worked like a charm. Thank you!