Validate user input to avoid creating malformed files

[utdemir]

Currently most of the inputs we allow are raw strings. The user can easily pass incorrect values (project names with disallowed characters, module names that does not fit haskell syntax).

We should have a script which validates them to ensure that the files we generate are correct.

It doesn't have to be a super strict validation, I am happy if a dedicated user can break it; but we should at least protect for simple mistakes.