Revert "Getting Started page (#11673)"

[epixa]

This reverts commit 211b3d4.

This was breaking builds, so we revert until we figure out why.

[epixa]

This isn't necessary if #11789 goes green

[ycombinator]

#11789 isn't going to go green because it is reporting this failure in https://kibana-ci.elastic.co/job/elastic+kibana+pull-request+multijob-selenium/4543/consoleFull:

 └-: console app
   └-> "before all" hook
   └-: console app
     └-> "before all" hook
       │ debg  navigateTo console
       │ debg  Clicking opt-out link
       │ debg  in findTestSubject: [data-test-subj~="lnkGettingStartedOptOut"]
     └- ✖ fail: "console app console app "before all" hook"
     │        Error: Timeout of 10000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.

This PR, however, is green so I say we merge this PR for now. I'll amend #11789 to include 211b3d4 and keep working on getting it green.

[epixa]

5.x c6baef8