Could esptool dependency removed? (ESPTOOL-1282)

[dobairoland]

Checklist

• Checked the issue tracker for similar issues to ensure this is not a duplicate.
• Provided a clear description of your suggestion.
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Issue or Suggestion Description

This project has a special kind of circular dependency on esptool. The stubs are used by esptool but esptool is required to build the stubs.

#47 introduces the plugin system and adds pyelftools dependency to tools/elf2json.py. After that change we could re-evaluate if the necessary code could be copied over here (effectively duplicated).

The task is to try the idea but discard it if too much code has to be moved, or the moved code is difficult to maintain.

If esptool dependency is removed, update the documentation and Github Actions as well.