Broken links in README.md and upgrade instructions

[Borgquite]

Hey, appreciate the work, as ever! Just to say I was checking out how to do something today and noticed a number of broken links to the internal documentation in README.md - perhaps since the documentation update?

Specifically all the 'more information' links, the 'profiles' link, and the 'README of that version' link.

Please could you fix?

Also wondering if you have any plans to issue a guide to upgrade between versions? Do we just deploy over the top? Do any version upgrades require us to wipe the working folder, for example, has the structure ever changed between versions? I've found that doing so can break renewals...

[glatzert]

I made a quick patch to have links placed to the docs, but I'll redo the README so it directs to the docfx pages, where appropriate

[Borgquite]

Thanks @glatzert :)