fcl-db: oracle:
- for ftBlob parameters binding use temporary LOBs instead of long varraw to bypass 64KB limit of current implementation
- initial support for NCLOB data type (if client uses for NCHAR "variable width" charset (like UTF-8) then there is character length <> byte length which is currently not handled correctly)

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@28286 3ad0048d-3df7-0310-abae-a5850022a9f2