fcl-db: oracle:
- bind date and datetime params using Oracle external data type SQLT_TIMESTAMP instead of SQLT_ODT to support fraction seconds
- introduce support for ftBlob and ftMemo params, but only with max.length up to 64K

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@28041 3ad0048d-3df7-0310-abae-a5850022a9f2