rewrite code editor for web

[k0l11]

In order to have a clean solution for:

• syntax highlighting
• code formatting
• autocompletion
• error detection
• ...

we should look into:

• defining gcsl as a grammar using ANTLR to generate a parser in TS/Golang
• this parser can then be used in combination with something like Monaco to implement the code editor
• example tutorial: https://betterprogramming.pub/create-a-custom-web-editor-using-typescript-react-antlr-and-monaco-editor-bcfc7554e446