Await TTD notice added for MergeReadiness [Fixes #511]

[wackerow]

Description

• Updates design of /merge-readiness page to include notices about waiting on certain tasks until the TTD has been announced and included in client updates.
• Design changes include dimming of the two tasks that should not yet be performed and disabling the checklist buttons.
• Adds "timing" note to the task cards

Related issue

• It's still early to prepare for the merge #511

Preview link

https://deploy-preview-514--serene-carson-3331d5.netlify.app/en/merge-readiness

[samajammin]

👍

[nloureiro]

Overall looks good!

Minor changes on the top squares.

• remove the green from the grey-out ones.
• time in bold
• align-items:start to align to the top of the squares.

other than that I don't see any blockers

[nloureiro]

sticky.mov

one nice to have: what do you think of having the headings sticky? helps me to know in what section I am when reading it more slowly. keep track.

then again, nice to have :)