The mapping between the "main" branch and the "production" Puppet
environment has been removed, so we update the doc accordingly.

refs team#41974

the biggest semantic change is in the sentence "This is actually
scheduled in two weeks" which sounds like we will run upgrades in two
weeks from now? or.. maybe two weeks after rfc deadline? which is not
what's meant.

Used in team#41829

the comment at the top of the playbook section will hopefully help us to
remember to keep the playbook URLs in order if we rename the section.

the debian package from trixie just renamed the exporter's binary in
last night's package upgrade.

Adds information about new roles.

See merge request !72

I'm guessing that disabling the archiver after having it enabled is not
a common case, but with this we should be able to remember how to clear
out the alert.

refs: team#41655

refs: team#41655

Helped debug boot failures in team#41829

I'm not 100% certain about what to do in the case that the archive is
valid, so I indicated that maybe we want to extract it in a subdir. we
can adjust that when we find a case where that happens. today's case was
a corrupted archive that we could delete.

this is in addition to what we can find with `gnt-instance info`

I did the onboarding with gillian and things were not quite right. The
top NOTE was particularly confusing.