Parse accessibility test output

[RobinKnipe]

Find a suitable [automated] accessibility testing tool and parse the test output so it can be included in the "Non-compliance with the accessibility regulations" section. This should allow for better testing automation and inclusion of accessibility testing in CI.
This feature should take test output (probably a JSON file) and produce a markdown snippet for inclusion in the standard template.
A template fragment for an issue should probably be created, for use here but also from other contexts.

[RobinKnipe]

This is similar to #7 and should help with that.

[RobinKnipe]

A suitable automated testing library could be Pa11y, that's probably the first we should evaluate for CI.