Update the parsing library

The objective is to have at least extension checking.
We have the following options :

• keep haskell-src-ext
• use a library to detect extensions
• use ghc library to parse or a ghc version independent library like ghc-lib or ghc-lib-parser

First step would be to do a POC of all three libraries.

• ghc-lib-parser POC
• extensions POC
• haskell-src-ext POC

Now that the noSig is working what's left is to;

• Fix the extensions check #47

Make all the rules

• NoSig
• FunctionTooWideOrLarge
• BadIf
• BadHeader
• BadGuard
• BadDo
• BadDoReturn

Create the new rules

• NoModuleDecl
• NoModuleExport
• ForbidenPragmaList
• UnauthorizedExtension

Removing the two last POCs since ghc-lib-parser is the best candidate.