[7.0] Refine IDE run configurations

[Jonathing]

ForgeGradle 7 currently works by registering tasks to run the game using Slime Launcher. Work needs to be done to better support adding run configurations for IDEs. Here's what that will most likely look like.

Eclipse

Eclipse run configurations will depend on how the Eclipse compiler and hotswapper handles the Gradle run tasks. If Eclipse cannot hotswap code using the run task, then the launch configurations will need to be created using the contents of the run tasks. On the other hand, if Eclipse handles the Gradle task well, then all that needs to be done is add a convenient way to access the run configurations, either by adding a launch file that only contains the Gradle task or some other way of adding it to the drop-down menu.

I'll be testing this thoroughly with @LexManos as it is a key requirement for both ForgeGradle 7 and ForgeDev 7.

IntelliJ IDEA

IntelliJ's debugger is attached to the process started by JavaExec, and thus treats it like a normal launch configuration. The only thing that should be done on this end is to add the run configurations to the drop-down menu. However, I'm hesitant to commit to this since the XML spec for run configurations has never been static.

Visual Studio Code

Same story with IntelliJ. If there's a way to add the run configs to the drop-down menu, that's what I'll do. I have no idea how the debugger on this one works, so I'll need to test myself later.

Any other IDE

Please use your IDE's native method of calling the Gradle run task in debug mode.