Add system plugins assembler, syntax hightlighting, docs and debugging

[Sefran007]

In general, it would be even better if there were a module system for assemblers, syntax highlighting, debugging, docs etc.

We could then add yasm, llvm-as, etc., along with their syntax highlighting, etc.

Loading and unloading language support, etc.

[Sefran007]

You can take inspiration from the KDE code for Plasma Kate...