fix doc highlighting oidc callback path

Fix docs template syntax error in OIDC SSO example

Add worker metrics to prometheus exporter

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/1158

Skip importing validate_config task when Synapse is disabled

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1145

Supersedes https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1145

GoMatrixHosting v0.5.1

Upgrade mjolnir (0.1.17 -> 0.1.18) and implement self building

Correct broken documentation link

Recently, documentation on Synapse has been changed from .rst to .md. Therefore, the current links for the purge history API were resulting in a 404 error.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/1154

According to
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy,
having both a header and the `<meta>`-tag provided by Element itself is
not a problem. The 2 CSP policies get combined.

Updating to latest synapse release (performance regression)

https://github.com/matrix-org/synapse/releases/tag/v1.37.1

postgres minor updates

Update IRC bridge

heisenbridge: fix service name in setup_uninstall.yml

Remove asterisks from configuring-dns.md

These previously denoted optional DNS records but now optional records are a separate table so they are unnecessary.

Update hydrogen main.yml

update to v0.2.0

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/1140

Update prometheus  v2.27.1 -> v2.28.0

Coturn update 4.5.2 -> 4.5.2-r2

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1131

The new one is based on Alpine 3.14, instead of Alpine 3.13.

Add support for CentOS (Stream) 8

according to discussion in channel not needed anymore

Content-Security-Policy For Element Web