Add MSSQL Support

I have been able to get mssql to work with rundeck after a few minor code changes. I've tested with the internal H2 DB, MSSQL2012, and Mysql 5.6.15 in a test instance using the war file and tomcat/jdk7. For MSSQL I used the microsoft JDBC driver and for Mysql I used the bundled driver. I couldn't test against oracle however; these changes use hibernate to choose the sql type rather than a hard coded one which should work properly with oracle. 
was it necessary to limit the size of this field?