[Ready] Remove FAQ documentation content, fix links

[stichbury]

NOTE TO REVIEWERS. You can see the built docs here.

Description

Part of #1985, and the milestone to improve the onboarding experience, paying particular attention to FAQs.

The overall plan is to:

Move marketing FAQs to the website

See this website issue for ongoing work.

Note The copy that will go onto the site is available for review in Box but is also dependent on our pending messaging discussion.

Add more technical FAQ content in the documentation where it's relevant

We now have a spaceflights FAQ, as one example. As we improve docs we will favour content that is structured to answer typical user questions (in part because SEO).

Why remove a popular page?

My thoughts on the fact that the FAQ page is currently a popular one in the docs are that people are looking for information, used to checking FAQs, so they visit the page.

They're not there to read the page end-to-end and -- I would guess -- they're not really getting much out of the existing content, which is a mixture of marketing copy, a list of names and a few technical details that didn't fit elsewhere.

Some people will also end up on the FAQ through organic search and we need to make sure that the copy (in Box, see note above) is optimised so they get to the Kedro website and find what they need.

I want to prioritise content in the coming weeks that fills any gaps left by the FAQ. So, aside from the website copy, we also need to do the following:

• Write a "Commonly asked questions about Kedro blog post (which may be this one)
• Create a revised blog post from Joel's data layers TDS post
• Make a new 'skinny' FAQ page in the docs that asks common technical questions, but doesn't answer them, it just pushes readers through to the relevant content (this page would use the Heap analytics data as a guide to determine where most popular pages are, and thus what likely questions we should answer -- we also have a collection from Joel and can review Slack for more)

Development notes

• Removed FAQ content and graphics that are no longer needed
• Moved the list of "Humans behind Kedro" to the root Kedro README
• Also removed the other two pages in the FAQ section
  • Kedro architecture overview (Ticket)
  • Kedro principles (Ticket)
• Fixed links where they pointed to removed content and updated the exclusions list in conf.py because the linkcheck doesn't understand anchors and I'm pointing to an anchor in Kedro's README

Checklist

• Read the contributing guidelines
• Opened this PR as a 'Draft Pull Request' if it is work-in-progress
• Updated the documentation to reflect the code changes
• Added a description of this change in the RELEASE.md file
• Added tests to cover my changes

[astrojuanlu]

Thanks a lot @stichbury! Left a few comments

[astrojuanlu]

With the addition of gh-2377 this PR looks good to me!

[stichbury]

I am not going to merge this PR until we have the following in place:

* Agreement on general messaging

• Updated copy for "marketing" FAQs (these are in Box)
• Transitioned those FAQs from their location in Box onto website
• Added a set of basic technical FAQs to the FAQ page in the docs

[merelcht]

This looks really good! ⭐ I left one minor comment.