Enhancement: Tile sizes

We've adjusted the tile sizes to have a bigger base size and smaller stepping from one tile size to the next.
In addition to that the default tile size has been changed to the second stepping, so that initially both
space tiles and file/folder tiles have a sufficient size for reading longer names.

https://github.com/owncloud/web/issues/10018
https://github.com/owncloud/web/issues/10638
https://github.com/owncloud/web/pull/10558
https://github.com/owncloud/web/pull/10646
