Core/Database: Converted the database library to a shared library.

* There is still the possibility to static link against database.

(cherry picked from commit 6cfea2d8f7)

src/server/database/Database/MySQLThreading.h

@@ -20,7 +20,7 @@
 
 #include "Log.h"
 
-class MySQL
+class TC_DATABASE_API MySQL
 {
     public:
         static void Library_Init()