Improve efficiency of building Internal.InfoTable

[lukaszcz]

The following code in Juvix.Compiler.Internal.Data.InfoTable takes ridiculously long:

letFunctionDefs :: (Data from) => from -> [FunctionDef]
letFunctionDefs e =
  concat
    [ concatMap (toList . flattenClause) _letClauses
      | Let {..} <- universeBi e
    ]
  where
    flattenClause :: LetClause -> NonEmpty FunctionDef
    flattenClause = \case
      LetFunDef f -> pure f
      LetMutualBlock (MutualBlockLet fs) -> fs

It is responsible for over 10% of compilation time.

The problem seems to be the use of generic traversal with universeBi and automatically derived instances. The documentation of uniplate mentions that one can achieve a 5x speedup by using Data.Generics.Uniplate.Direct instead of Data.Generics.Uniplate.Data and implementing the instances manually.