Add support for DB2

[3URNINGCHR0M3]

I'm evaluating using auto patch for a system which uses DB2 as the back end.

I have started working on changes to SQL properties file, but I have not implemented the full life cycle of a patch yet.

I'll create a pull request for this issue when I'm done.

[scottfromsf]

Thanks, 3URNINGCHR0M3. Looking forward to the PR.