Re-enable when all servers have been upgraded to systemd 251.

Order and exact values copied from the CF example in resolved.conf.

Fix #371

Hetzner DNS has been delaying many responses for 5 seconds, causing
outgoing federation work to pile up, almost running into OOM before we
noticed.

I don't know if were being throttled because federation makes a *lot* of
requests. Anyway, using Cloudflare DNS seems to solve it.

Enable DNSOverTLS for this because we can.

Leonidas Spyropoulos authored 3 years ago and Kristian Klausen committed 3 years ago

This is shared between common and install_arch roles

Closed: #288

Signed-off-by: Leonidas Spyropoulos <artafinde@gmail.com>