The cleanup includes the following changes:
- The `esptool.py` is no longer installed as a RIOT package, but as a pure Python package, as published by Espressif. The installation takes place in a virtual Python environment in the `dist/tools/esptools/venv` directory.
- The installation of the `esptool.py` is now version-sensitive.
- The `esptool.py` from the Python package is always used.
- The option for users to use a custom `esptool.py` has been removed because newer versions of `esptool.py` use renamed options that are not compatible with older versions of `esptool.py`. Using a custom `esptool.py` therefore makes no sense.