This change adds the new createSchemaManager() to
our Doctrine DBAL Connection subclass to make it
forward-compatible with Doctrine DBAL 3.x.

createSchemaManager() is introduced with DBAL 3.x and
is replacing getSchemaManager() which will be removed
in Doctrine DBAL 4.

Since this is a very lowlevel change, the method
can be added without most notice for extension authors.

Resolves: #96286
Releases: main, 11.5
Change-Id: Ifdccc2b0dff443bfe38d23a1bd1333b5c7c5db40
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72555

Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>