Add missing docs that should be on 1.10 release branch

[raskchanky]

I'm not confident that I've done this correctly, but let me detail what I've actually done and maybe someone can correct me if I'm wrong. The goal here is to add docs to the 1.10 release branch that should be there, but aren't.

For context, see the discussion starting here #14927 (comment)

I originally attempted to calculate the diff between the release/1.10.x and stable-website branches, constrained to the website directory, but that proved an exercise in futility. The resulting diff I got wouldn't apply cleanly to release/1.10.x, which made me feel like I was going about this wrong.

In the end, instead of diffing release/1.10.x and stable-website, I diffed release/1.10.x and main, figuring that all docs changes would've been merged to main anyway. Here are the exact commands I used, starting from a freshly updated main branch:

$ git checkout -b release/1.10.x origin/release/1.10.x
$ git checkout -b add-missing-docs
$ git diff --output=website.patch release/1.10.x..main -- website
$ git apply website.patch
$ rm website.patch

I think this should have the effect of bringing over all the changes that have been made to the website directory on the main branch into the release/1.10.x branch. I'm not certain I got this correct however, and would appreciate some extra eyes. The litmus test I was using was checking to see if the MFA docs I wrote were added, since those should be on the release/1.10.x branch.

[raskchanky]

Tagging @kalafut @ldilalla-HC @peaceofthepai @mladlow here at Meggie's request.

[stevendpclark]

Looked through the changes to all relevant docs for the crypto-sec team, (SSH, PKI, managed keys, hsm, seal). All these changes look good to me and should appear on 1.10 branch.

I also agree with the technique used to generate the diff, for at least the crypto-sec related stuff nothing will be backported that is targeting 1.11 that I can see.

[kalafut]

A quick diff against stable-website looked reasonable. I'm good with merging. We can still fix things up if we discover missed items.

[kitography]

I'm too late, this is cool updates and correct, but submitting review so typo-references exist.

[mladlow]

I'm late to this party but thanks for following up on this @raskchanky !