Automatic check for page-specific `<title>`s (OSOE-1256)

[Piedone]

For UX and SEO, it's good if pages have unique <title>s, or at least one that's actually specific to the page. So, having only the site name in the title is bad. Let's have some check for this.

Perhaps we could assert that page title != site name. Checking for unique titles would be even better, but for that we’d need to crawl much of the site in a single test, which isn't necessarily feasible, and would make using this feature harder than just flipping a switch. However, we could still do it so at least the pages already visited in the test have unique titles, and allow a full crawl if people want that.

• Add an assert that page title != site name.
• Add an assert that page titles are unique.
• Make these configurable similar to how accessibility checks, HTML validation, and SQL Query Monitoring works: ability to turn it off and on globally, set rules when the check should run (see e.g. AccessibilityCheckingAndAssertionOnPageChangeRule), and set the assertion logic.

Jira issue