separate AgSpaceStuff and AgShipShake

[red031000]

This should fix the below error on server startup

[07-12-21 04:58:49] [CppScripts]: Attempted to load CppScript for 'scripts\ai\AG\L_AG_SHIP_SHAKE.lua', but returned InvalidScript.

I have tested myself in game on a new character and verified that the desired functionality is present
The elimination of the error should also help people asking for help (and those providing help) in setting up the server, as they do not go looking for issues in potentially the wrong place (also it's an elimination of an error, which is always nice)

I've also fixed a cmake warning in the PR

[MickVermeulen]

LGTM, next time try to separate commits into concrete sections, e.g. when just looking at the message "separate AgSpaceStuff and AgShipShake" it's not clear that it also changes the CMakeFile. Non blocking tho, just something to keep in mind going forward to keep the commit history clean.

[MickVermeulen]

Tested, works great. Thanks for the contribution!

[MickVermeulen]

Wanted to comment on this: please make sure that your commits and your PRs semantically match what you're contributing. I now approved the commit and was just waiting to test it after which core functionality in Entity.cpp was edited which was not at all reflected in the PR name. If you want to work on multiple things locally you can create local branches using git checkout -b <branch-name> and create pull requests for each of them separately, this makes it way easier for us to review the contributions you make.