borg: Remove soju from sqlite backup

Soju is using postgres now.
soju: Change to soju-srht

Use postgres instead of sqlite3.
gamja: Use with soju-srht

Config.json is now served by soju.
DNS: Update records, remove IPv6 srht records

Using IPv6 causes a bug that will keep users from registering.
grafana: Rename datasources provisioning file

Is now used for alertmanager as well.
grafana: Upstream config update, use alertmanager integration
srht: Store GPG keys in vault as well

This enables a better auto-deploy pipeline.
ssh: Fix folder permissions

With the old permissions my user could not read the file and would not
respect my ssh configuration (e.g. HashKnownHosts).
avalon: Set custom hostname
setup_archlinux: Set hostname and symlink resolv.conf

Hostname can be set by a variable. If not set, it will be read from the
ansible inventory.
grafana: Provision first simple dashboard
srht: Add paste api
croc: Upstream config update
prometheus: Change critical updates severity to warning

Don't really need to act immediately.
prometheus: Improve instance labelling

Removed ports and changed localhost to xenrox.net for better
setup_archlinux: Install timer to reboot system
prometheus_clients: Add missing systemd files for arch script
cron: Remove reboot task

Will be substituted with a systemd timer.
prometheus: Add alert for critical updates
prometheus_clients: Gauge critical security updates