use interactive text editor in frontend

[cs01]

Is your feature request related to a problem? Please describe.
When debugging a program, the program cannot be modified in the gdbgui interface. It has to be opened else where, then saved. This can be cumbersome.

Describe the solution you'd like
Use an interactive code editor in the web UI, such as Microsoft's Monaco as a text editor instead of hand-made React component. This essentially enables all of VSCode's language service capabilities in the browser, such jump to definition, language-specific semantic understanding of variables for things like hover. Adds ability to edit+save files. Also must support inline disassembly display.

Describe alternatives you've considered
Use a text editor or IDE.