Modify xtrn-setup to support third-party doors

Create a new dir in xtrn to hold ini files (install), which will be contributed to the repo

In the inis have the filename to look for, and md5 hashes

When setup runs, it will check all those inis to see if it can match with any dirs in the xtrn dir using the filename and hash

exe['game'].md5['xxx'].ini = path/to/ini // mapping

If so, it will use that ini file to install the game