Allow custom TTS API

[RenMeow1]

Problem

Currently it uses the system TTS, which is very poor and robotic.

Proposed solution

Allow users to check a option to specify a custom web TTS api address, and a optional api key. There are plenty of services out there that are free or cheap for high quality TTS, even local TTS services.

Notes (optional)

No response

Checks

• I searched for existing discussions and didn't find a duplicate.