We keep the pager / disaster stuff at the end of the section so it's
easier to find.

Add instructions for changing branch names

See merge request tpo/tpa/wiki-replica!9

We'd this in MRs CI:

    /bin/bash: line 131: git: command not found

Doh.

Explain how to send the signed challenge to change the sudo password

See merge request tpo/tpa/wiki-replica!8

This moves a some documentation out to a better onboarding scenario,
which points to each individual page for specific procedures

I do this because i keep getting lost in the pages. At least now at
the top there will be a pointer to a ticket which has the full list
and identifies the problems clearly.

This is so the document can be read by the new person more easily

The comments were misrefering to things

This is necessarily going to fail.

VM requirements

See merge request tpo/tpa/wiki-replica!6