[TASK] Structural refactorings

Removed all css files from Resources/Private/Templates/Extensions/...
and inserted them into the main structure.
Adopted the TypoScript to ommit the missing CSS files.
Merged all tx-find css into one scss file and put it under _Includes
in the main Scss directory.
Merge pull request #20 from subugoe/refactorings

[TASK] Structural refactorings