[FEATURE] Add a the posibility to open/close leafs

It is now posible to make the fileTree dynamic.
As in open/close folders. The state can be saved in
user session so on return last state is shown.

You need a little bit javascript that depends on jQuery
to get this working. See TypoScript/setup.txt
[BUGFIX] Change cms core dependency in composer.json

The composor name of CMS core has changed from typo3/cms/core to
typo3/cms-core.
[BUGFIX] Make tree action non-cached

Because the tree action was cached the tree isn't collapsed
after a refresh.