[FEATURE][INSTALL] Check MySQL privileges to create new databases

Hide the option to create a new MySQL database within the 1-2-3 wizard,
if the MySQL user has no permissions to do so.

Change-Id: Ia1dac4ff39e9254d91b4b044306dbb6600df1525
Resolves: #27194
Releases: 4.7
Reviewed-on: http://review.typo3.org/2507
Reviewed-by: Andreas Wolf
Tested-by: Andreas Wolf