ControlFreak: Enhance LFS to allow "white listing" of file types

[Jim Howard]

In the General Policy > Large File Policy section of ControlFreak, a very useful option (of the “Block all large files” sub-option) would be to add a way to not enforce the Large File Policy on certain file types. There is currently an option to do the opposite (force Large File Policy on certain file types); it seems reasonable to also provide exceptions.
A specific use model would be to not enforce LFS on .cs files, even if they are larger than the value specified by the default policy. This would be extremely useful for our repositories!