This page really is a mess now, ugh.

This is causing locale problems that I can't reproduce locally, but
that still exist, so let's just silence this for now.

Example:

https://gitlab.torproject.org/tpo/tpa/wiki-replica/-/jobs/687276

Excerpt:

$ ./bin/mdl-wrapper $(cat changed-files.txt)
checking file service/donate.md...
/usr/share/rubygems-integration/all/gems/mdl-0.13.0/lib/mdl/doc.rb:39:in `split': invalid byte sequence in US-ASCII (ArgumentError)
	from /usr/share/rubygems-integration/all/gems/mdl-0.13.0/lib/mdl/doc.rb:39:in `initialize'
	from /usr/share/rubygems-integration/all/gems/mdl-0.13.0/lib/mdl/doc.rb:50:in `new'
	from /usr/share/rubygems-integration/all/gems/mdl-0.13.0/lib/mdl/doc.rb:50:in `new_from_file'
	from /usr/share/rubygems-integration/all/gems/mdl-0.13.0/lib/mdl.rb:91:in `block in run'
	from /usr/share/rubygems-integration/all/gems/mdl-0.13.0/lib/mdl.rb:83:in `each'
	from /usr/share/rubygems-integration/all/gems/mdl-0.13.0/lib/mdl.rb:83:in `run'
	from /usr/share/rubygems-integration/all/gems/mdl-0.13.0/bin/mdl:10:in `<top (required)>'
	from /usr/bin/mdl:25:in `load'
	from /usr/bin/mdl:25:in `<main>'

This reverts commit 3b2ba6cb.

POLA: principle of least astonishement. for an admin not familiar with
the blackbox exporter, that `curl` is a huge WTF. so we instead show
the more familiar nc command, and also explain what it does.

*then* we introduce the blackbox stuff.

with the move I should've fixed that

I wanted to place this further down but failed to see the same section
names were also present in the section Installation.

It's clear enough in the upsteam readme, but it's nice to have a
reference to this trick closer to our eyes.

We currently have a gitlab-runner warning pending and the playbook
didn't cover it at all.

Boom:

/usr/share/rubygems-integration/all/gems/mdl-0.13.0/lib/mdl/doc.rb:39:in `split': invalid byte sequence in US-ASCII (ArgumentError)

According to iconv, that's:

$ iconv -f ascii -t utf-8 howto/postgresql.md > /dev/null
iconv: illegal input sequence at position 41113

Which is the "bullet" ("●", U+25CF BLACK CIRCLE) in the systemctl
output.

https://gitlab.torproject.org/tpo/tpa/base-images/-/jobs/683968 ran
correctly, but the image was unchanged so the new tag didn't make it.

We'd use our own image here, but i can't find a stable-backports image (base-images#13).

This will reduce the impact on Docker hub rate limiting and improve
our supply chain, among many other things.

Those are queries I often find myself having to dig out of dashboards
and alerts, but that are useful on their own.

Describe a smtp_tls_policy_maps setup

See merge request !57