ARIA-AT coverage metrics

[jscholes]

I'm creating this issue to track ARIA-AT coverage reporting efforts.

Done so far

• Created an initial report layout/page, at https://github.com/w3c/aria-at/blob/master/metrics/coverage.md.
• Added introductory header, plus the following sections:
  • Project Coverage at a Glance;
  • Project Statistics;
  • APG Design Patterns;
  • APG Examples;
  • ARIA Roles; and
  • ARIA States and Properties.
• Added the total number of APG design patterns, plus the tested count and percentage, to the "Project Coverage at a Glance" table.
• Added the list of APG design pattern names to the "APG Design Patterns" section.
• Filled out the rest of the "Project Coverage at a Glance" rows.
• Filled out the "Project Statistics" list.
• Added links to the APG design pattern names in the "APG Design Patterns" section.
• Added lists of links to the "APG Examples", "ARIA Roles", and "ARIA States and Properties" sections.
• Added a "last updated" date.
• Added links to other key project resources in the intro.

Still to do

• Automate the generation of the data on this initial report.
• Incorporate automated generation into GitHub workflows so that metrics are automatically updated for every new test plan.
• Add some or all of the following totals in some fashion:
  • test plans, tests and/or assertions per APG design pattern;
  • test plans, tests and/or assertions per APG example;
  • test plans, tests and/or assertions per ARIA role;
  • test plans, tests and/or assertions per ARIA state;
  • test plans, tests and/or assertions per ARIA property; and
  • tests and/or assertions per test plan.

[jscholes]

@mcking65 Which links do you want added to the metrics document? As per the November 11th CG call, I think we want links to the ARIA-AT App home page, and test plan builds page, as a minimum. Any others, or alterations to those?

[jscholes]

The coverage report has been updated, with all initial figures and lists, plus some links and a "last updated" date at the top.