Investigation Effort goals and tracking

[foolip]

We have 2 investigation efforts accepted in Interop 2023: Accessibility Testing and Mobile Testing.

We'll need a main point of contact for each, as well as a GitHub repo for collaboration. Then we'll need to agree on the detailed goals and how we'll communicate progress during the year.

I think we have an opportunity to improve compared to 2022, see #157 for some feedback we got then.

[jgraham]

We already have GitHub repos for each: https://github.com/web-platform-tests/interop-2023-mobile-testing and https://github.com/web-platform-tests/interop-2023-accessibility-testing

[zcorpan]

Status for Accessibility Testing is tracked in web-platform-tests/interop-accessibility#3

We've also updated the score on https://wpt.fyi/interop-2023