Refactor DOMenvironment loading & parsing files

Currently the way DomEnvironment loads and parses files / directories is coupled and contained lot's of copy-paste. One of the example is DomEnvironment::loadFile.

Moreover, the following things are currently coupled:

1. Creating Env / Univ inside the DomItem::loadFile (this is questionable)
2. Parsing files(meaning instantiating lexer / engine) is done inside the constructors of the files
3. It's not clear how many of the "features" are actually being used
4. Loading / parsing is happening through the ParsingTask being placed to Queue... Which is handled by the DomUniverse(??).
5. There are some bugs, for example in DomItem::loadFile, callback is being called with Paths::qmlFileInfoPath, however there are other possibilities, for example qmldirFileInfoPath and jsFileInfoPath.
6. Some other unknown stuff to be discovered caused by 1&2

Overall, I think better separation of concerns and modularity has to be introduced there.