audio/py-pyttsx3: Add port

Offline Text To Speech (TTS) converter for Python. Unlike alternative libraries, it works offline.

Requires some post-release commits from Github due to dependency on audio/espeak-ng[1]. If release version 2.90 is installed via e.g. PIP instead, it will not find audio/espeak's libespeak-ng.so.1 library.

The port is needed as one of the dependencies of the QGIS plugin 'QChatGPT'.

[1] https://github.com/nateshmbhat/pyttsx3/commit/1e2cd7fc63671a410e6ca7b53b1e3b048577e962