Allow triggerPaths to include wildcard for repository name

[dagood]

This would let us avoid listing every aspnet repo individually in #306.

I'd expect changes to be pretty limited to here:

versions/Maestro/src/Microsoft.DotNet.Maestro.WebApi/Models/SubscriptionsModel.cs

Lines 75 to 95 in 93cc2cd

	private IEnumerable<Subscription> GetSubscriptions(ModifiedFileModel modifiedFile)
	{
	return Subscriptions.Where(s => s.TriggerPaths.Any(p => Matches(p, modifiedFile)));
	}
	private bool Matches(string path, ModifiedFileModel modifiedFile)
	{
	bool matches = string.Equals(path, modifiedFile.FullPath, StringComparison.OrdinalIgnoreCase);
	if (matches)
	{
	return true;
	}
	if (path.EndsWith("/**/*", StringComparison.OrdinalIgnoreCase))
	{
	string rootPath = path.Substring(0, path.Length - 5);
	return modifiedFile.FullPath.StartsWith(rootPath, StringComparison.OrdinalIgnoreCase);
	}
	return false;
	}

Maybe it should change to full-blown regex. (Also solving #207.)

/cc @mmitche