Misc: Accessibility rules update

* Changes to the status of the WCAG rules that are currently not violated. From this point on, all changed rules will make the build fail.

As of https://ci.xwiki.org/job/XWiki%20Environment%20Tests/job/xwiki-platform/job/master/506/, there are only a few rules that fail through tests:
- aria-allowed-attr 1 violation
- label 76 violations
- image-alt 1 violation
- link-in-text-block 409 violations
- select-name 2 violations
- color-contrast 2 violations
- scrollable-region-focusable 1 violation

Total violations: 492

* duplicate-id fixed
* duplicate-id-active fixed
* duplicate-id-aria fixed