Add option to verify-dotnet-consolidation to ignore projects matching a given pattern (OSOE-859)

[Piedone]

Add option to verify-dotnet-consolidation to ignore projects matching a given regex pattern. The idea is that the action would then do this:

1. use dotnet sln solution.sln remove excluded.csproj to remove the matching projects from the solution.
2. Run dotnet-consolidate.
3. Restore the solution with git reset --hard.

Idea by @sarahelsaig.

The regex pattern should match web projects by default.

We need this for our reusable Orchard Core modules/themes so they can target the .0 minor version of the latest version; i.e., 1.8.0 currently, so people can use them regardless of the consumer projects being on 1.8.0, 1.8.1, 1.8.2, or 1.8.3 (currently they're forced to use at least what the projects target).

This is also necessary for Orchard Core Commerce: OrchardCMS/OrchardCore.Commerce#449.

This will be especially important after OC 2.0, since that'll strictly follow SemVer, not releasing breaking changes with minor versions. So, we might want to keep our modules/themes targeting 2.0 until 3.0 is released.

This started under Lombiq/Helpful-Libraries#258 and OrchardCMS/OrchardCore.Commerce#435 (comment).

Jira issue