[TASK] Dashboard should show custom projects first

Kickstarting an extension's manual or converting an OpenOffice manual
is supposed to be less important in the middle term. As such custom
project tab should come first.

Change-Id: I463f9e29705117e3810543f7bc30c85c39693de2
Reviewed-on: https://review.typo3.org/29090
Reviewed-by: Xavier Perseguers
Tested-by: Xavier Perseguers