script: redesigned scripts to work based off of CMD instead

rebuildDocker.bat

@@ -1,2 +1,4 @@
 @echo off
-powershell .\rebuildDocker.ps1
+echo .\gradlew Server:jar | cmd
+docker build -t server-testbuild .
+# docker run --rm -e "MMU_LOG_LEVEL=5" -p 1218:1218 server-testbuild

updateSubmodule.bat

@@ -1,2 +1,7 @@
 @echo off
-powershell .\updateSubmodule.ps1
+git submodule update --init
+cd .\Gamelib
+git fetch
+git checkout gamelib
+git pull
+cd ..