Add start script handling for Distributions tasks

[arlaneenalra]

This code does two things:

• Adds code to handle updating CreateStartScripts configuration in the same way that the JavaExec task is updated. This allows the assembleDist task to create usable startup scripts.
• Updates the build to gradle 7.4.2 (Mainly because I only have access to an M1 Mac and can't build with gradle 5.5.1)

To accomplish this, I abstracted the common behavior in ExecTask into a JavaFXTask base class and added the StartScriptsTask. This is probably not the cleanest implementation but it appears to work in my local testing.

It may be possible to back out the gradle update, but I would have no way to test that.

[arlaneenalra]

@jperedadnr or @abhinayagarwal my apologies if this is a breach of protocol, what's the best way to get reviewers for a pull request?

[sschuberth]

This PR has conflicts now that #151 was merged.