Rework Docker support

- Use multi-stage build for the application image
- Utilize connection pool init timeout for waiting on database container startup,
"docker-compose-wait" dependency is no longer required
- Override database host through environment variable - used in docker-compose
- Rename database scripts for explicit ordering (db container loads them alphabetically)

config.yaml

@@ -162,7 +162,8 @@ server:
     USE_THREAD_TRACKER: false        #[SEVERE] This deadlock auditing thing will bloat the memory as fast as the time frame one takes to lose track of a raindrop on a tempesting day. Only for debugging purposes.
 
     #Database Configuration
-    DB_URL: "jdbc:mysql://localhost:3306/cosmic"
+    DB_URL_FORMAT: "jdbc:mysql://%s:3306/cosmic"
+    DB_HOST: "localhost"
     DB_USER: "cosmic_server"
     DB_PASS: "snailshell"
     INIT_CONNECTION_POOL_TIMEOUT: 60    # Seconds