Debugger: remove build options and exclusively use "preLaunchTask"

[Hezkore]

The debugger currently has its own set of build options.
These should be removed and replaced with the built-in preLaunchTask launch configuration, combined with the ${defaultBuildTask} variable.
A build task also needs to be generated if it doesn't already exist.

[Hezkore]

I gave this one a try, but the biggest issue here is that opening and "running" single files will not work.
It relies too heavily on the launch and tasks json files, and cannot really use our "fake internal task".

I'll have to ponder on this...

[GWRon]

Is one of the main issues I have too. It is not made to quick and dirty prototypea, code-try-outs...

[Hezkore]

The current method allows for rapid prototyping by using an internal non-existant task by default.
But preLaunchTask cannot access this task, as it doesn't actually exist.
So in order to keep the quick compiling functions intact I will not implement this for now.