Database format resolved centrally in connection pool

Fix aiming performance improvement in the loading of condition.
The resolution of the database format ( in case of existing tables in the target DB) is done centrally at the first connection. For a given connection string, the db technology is stored and re-used for further connections.

PAckages involved:
CondCore/CondDB
CondCore/DBCommon
CondCore/DBOutputService
CondCore/ORA
CondCore/Utilities