Added Mautrix Google Chat

Also fixes the appservice and homeserver tokens for the Googlechat bridge,
so that they're not the same as the ones for the Hangouts bridge.

Also indicates that the Mautrix googlechat bridge is a replacement for hangouts.

From the [Synapse 1.43.0 release highlights](https://matrix.org/blog/2021/09/21/synapse-1-43-0-released):
> Asks clients to prefer [room version 9](https://github.com/matrix-org/matrix-doc/pull/3375) when creating restricted rooms ([#10772](https://github.com/matrix-org/synapse/issues/10772)), via the API defined in [MSC3244: room version capabilities](https://github.com/matrix-org/matrix-doc/pull/3244).

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/1322

GoMatrixHosting v0.6.2

Update matrix-appservice-slack (1.5.0 -> 1.8.0)

Update configuring-playbook-dimension.md

I am not using this bridge and haven't tested this but multiple people have said 1.5.0 isn't working and 1.8.0 works for them so it seems to make sense to update.

https://github.com/matrix-org/matrix-appservice-slack/issues/618#issuecomment-929849093

add how to generate htpasswd