Extended ItemDB to support several other formats (part 1)

- Updated item_db.conf in preparation for the source edits.

Signed-off-by: Haru <haru@dotalux.com>
Extended ItemDB to support several other formats (part 2)

- Actual source edits

Signed-off-by: Haru <haru@dotalux.com>
Removed some files which are not used
Updated db2sql converter to match the recent item db changes

Signed-off-by: Haru <haru@dotalux.com>