[BUGFIX] ADOdb: support NOT NULL/DEFAULT field attributes on BLOB/TEXT fields

Instead of globally disallowing NOT NULL and DEFAULT field attributes
make these attributes configurable per DBMS system.

Data dictionaries for PostgreSQL and MySQL are adjusted to match
the supported options.

Resolves: #67442
Releases: master
Change-Id: Ic0fb7a07ef4db9fc854489165ebc079382c2f011
Reviewed-on: http://review.typo3.org/40398


Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>