Update release (release-0.30.0 -> release-0.31.0)

See:
- https://github.com/vector-im/element-web/releases/tag/v1.8.4
- https://matrix.org/blog/2021/09/10/pre-disclosure-upcoming-critical-fix-for-several-popular-matrix-clients

This reverts commit e913347fe1.

Upgrade grafana (8.1.2 -> 8.1.3)

* add timeout param for nginx proxy

default value matrix_nginx_proxy_request_timeout is 60s

* default matrix_nginx_proxy_request_timeout - 60s

* few more variables for request timeout

* Update nginx.conf.j2

* Update nginx.conf.j2

This reverts commit 732051b8fc.

There's no such container image published yet.

http://nginx.org/en/CHANGES

Synapse 1.41.1 Patches 2 exploits that can reveal information about rooms an user is not supposed to have access to information about.

Update prometheus (2.29.1 -> 2.29.2)

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1247

Fix incorrect docker version tag for matrix-appservice-irc

Related to https://github.com/devture/exim-relay/pull/11

This bridge doesn't support SQLite anyway, so it's not necessary
to carry around configuration fields and code for migration from SQLite
to Postgres. There's nothing to migrate.

This configuration is supposed to be kept clean and not reference variables defined in other roles.

`group_vars/matrix_servers` redefines these to hook our various roles together.

https://github.com/matrix-org/matrix-appservice-irc/releases/tag/0.30.0

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/1236