Add DB2 support

add create DB2 database/user and get DB2 sql_connection logic

Change-Id: I17bc8add8c2558429b1675458e53e2e16b1950ac
Implements: blueprint db2-support
Initial rubocop support.

Per the mailing list thread, introducing Rubocop as a replacement for Tailor.
Assuming Jenkins likes this, more pedantic patches will follow to make Rubocop
happy.

Change-Id: I356c7846e85ae0ecaeb40c22b85431cdd5bd02a5
Merge "Initial rubocop support."