switch_core: Add capability to specify core-db-name in switch.conf.xml to have sqlite...

switch_core: Add capability to specify core-db-name in switch.conf.xml to have sqlite in a different location.  This is important for everyone with relatively 'high' sip registration since the addition of sip registration to the core require sqlite db to be moved to a faster location (Ramdisk for example). Useful for everyone who moved their sqlite db for sofia to ramdisk because of performance issue.