Accessibility testing

[GentlemanHal]

We can create automated tests using pa11y.

[GentlemanHal]

I've been trying the aXe Chrome extension to test as it can easily scan any page after all the dynamic content has loaded.

The biggest issue it's reporting is Elements must have sufficient color contrast, so this is something we should look into and update.

[GentlemanHal]

I ran a11y.css (which required messing with our Content-Security-Policy) and it raised some issues.

[GentlemanHal]

I've fixed the issues raised by a11y.css and have included checks in the journey test.

We also have issue #211 which we need to play to fix the contrast issues on the build labels and times on the Monitor page.

Ideally we need to get a human to look at accessibility, so if anyone knows anyone who can help us out that would be awesome.

I'm going to close this issue, we can raise specific issues if any other problems are found.