Add wechat bridge

Feature requests to add WeChat bridges have been made dating back to 2020 (https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/701), and again in January of this year (https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/3092).

Tobias Diez has already posted a merge request to add Ansible integration for this bridge (https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3241). I believe now would be a good time to make this happen, as I would really like to have a managed WeChat bridge on my etke.cc Matrix instance. This will be particularly beneficial for people who need to use WeChat to stay connected but don't want to install the official app on their computer.

@etke.cc I want to pay to make that done. I have a WeChat account and can help test this bridge. I would also like to invite developers to register one.