Feature: More agile Code block edit flow

[DiegoBoy]

Closing and reopening the embedded code editor has been the biggest time sink I've encountered working with code in Grid Editor.

When you want to open a code block in the editor and the editor already has another code block opened you need to close that one first. There's two improvements that would make working with code feel much nicer:

1. If the code that is already opened doesn't need "committing", it should be automatically closed and replaced by a new code block when you double-click it.
2. Making the code preview window editable without having to necessarily open the full view. This has the plus of helping you switch between to blocks easily - editing back and forth many times between two blocks is painful today.

[jamhed]

@DiegoBoy , check this out: https://github.com/jamhed/intech-grid-en16/blob/main/docs/lua-config-guide.md