TMDM-7524 : "The web server does not work after loging it use DB2 database."

Raised limit for CLOBs to 1 MB (iso. of 255 bytes by default) in schema creation.
Adds property "progressiveStreaming=2;" to JDBC URL to prevent closed CLOBs issues.
(https://jira.talendforge.org/browse/TMDM-7524)