Enhancement: Add Keyboard navigation/selection

We've added the possibility to navigate and select via keyboard.
- Navigation:
    - via keyboard arrows up/down for moving up and down through the rows of the file list
- Selection
    - via keyboard space bar: select / deselect the currently highlighted row
    - via keyboard shift + arrows up/down: add a series of rows
    - via keyboard cmd/ctrl + a: select all rows
    - via keyboard esc: deselect all rows
    - via mouse holding cmd/ctrl + left click on a row: add/remove the clicked item to/from the current selection model
    - via mouse holding shift + left click on a row: add the clicked row and the series of rows towards the most recently clicked row to the current selection model.

https://github.com/owncloud/web/pull/7153
https://github.com/owncloud/web/issues/6029
https://github.com/owncloud/web/pull/7280
https://github.com/owncloud/web/pull/7283