fix(ut3): install default configs from Game-Server-Configs (#5062)

ut3server had no install_config block, so a fresh install only had the
configs the game generates during fix_ut3. The web admin was disabled on
port 80 and UTGame.ini had no AdminPassword.

Download UTGame.ini, UTWeb.ini and UTEngine.ini into the ConfigSubDir
before fix_ut3 runs, then set the server name and a random admin
password. UT3 keeps pre-placed configs untouched when it generates the
rest, so the web admin is enabled on 7779 with the admin password.

lgsm/modules/install_config.sh

@@ -797,6 +797,11 @@ elif [ "${shortname}" == "ut2k4" ]; then
 	fn_default_config_remote
 	fn_set_config_vars
 	fn_list_config_locations
+elif [ "${shortname}" == "ut3" ]; then
+	array_configs+=(UTGame.ini UTWeb.ini UTEngine.ini)
+	fn_default_config_remote
+	fn_set_config_vars
+	fn_list_config_locations
 elif [ "${shortname}" == "ut99" ]; then
 	array_configs+=(Default.ini)
 	fn_default_config_remote