Revert "Create libraries based on external unmanaged directories (#147)"

This reverts commit 1934558595.

gaseous-tools/Database/MySQL/gaseous-1004.sql

@@ -1,11 +0,0 @@
-CREATE TABLE `GameLibraries` (
-  `Id` int NOT NULL AUTO_INCREMENT,
-  `Name` VARCHAR(255) NOT NULL,
-  `Path` longtext NOT NULL,
-  `DefaultLibrary` int NOT NULL DEFAULT '0',
-  `DefaultPlatform` bigint NOT NULL DEFAULT '0',
-  PRIMARY KEY (`Id`)
-);
-
-ALTER TABLE `Games_Roms` 
-ADD COLUMN `LibraryId` INT NULL DEFAULT 0 AFTER `MetadataVersion`;