SEO: improved titles for Skosmos 3 generated HTML pages

[osma]

Reasons for creating this PR

Improve search engine optimization in Skosmos 3 by making the <title> values and related metadata (title, twitter:title, og:title) conform to the specification in #1533 (comment) .

This PR only handles the titles, not descriptions. The descriptions will have to be implemented in a subsequent PR.

Link to relevant issue(s), if any

• Part of Search Engine Optimization for Skosmos 3.0 #1533

Description of the changes in this PR

• refactor: pass the GlobalConfig instance to the Twig templates, instead of individual configuration settings in separate variables
• adapt the Twig templates to use the GlobalConfig instance, and set their title metadata to match the specification
• add Cypress tests to verify the title values

Known problems or uncertainties in this PR

Checklist

• phpUnit tests pass locally with my changes
• I have added tests that show that the new code works, or tests are not relevant for this PR (e.g. only HTML/CSS changes)
• The PR doesn't reduce accessibility of the front-end code (e.g. tab focus, scaling to different resolutions, use of .sr-only class, color contrast)
• The PR doesn't introduce unintended code changes (e.g. empty lines or useless reindentation)

[sonarcloud]

Quality Gate failed

Failed conditions
54.1% Duplication on New Code (required ≤ 3%)

See analysis details on SonarCloud

[joelit]

There does not seem to be a translation string for 'Error':

• I tried with pages like https://localhost/Skosmos/yso/fi/p%C3%A5ge/p23406
• Then again, grep -C 1 'Error' skosmos_fi.po didn't show a msg-id that would be just 'Error'

The 'error' msgid should probably be added to the translation templates.