Add MariaDB support (#156)

* Fixed startup db check

* Relation tables are created automatically for IGDB metadata

* Removed JSON dependency from filters

* Removed JSON searches from Game library queries

* Gaseous now runs without error on MariaDB

* Fixed static database name bug

* Updated docker files and README

gaseous-tools/Database/MySQL/gaseous-1003.sql

@@ -1,2 +1,2 @@
 ALTER TABLE `PlatformMap` 
-ADD COLUMN `AvailableWebEmulators` JSON NULL;
+ADD COLUMN `AvailableWebEmulators` longtext NULL;