[5.2] SEF: Add "Strict Routing" option

[Hackwar]

Summary of Changes

Joomla has been improving its SEO performance constantly and with hopefully 5.2 we will allow for a stricter routing, which removes a lot of duplicate content. This PR introduces a switch to enable all these new behaviors, but does not implement them itself. It is basically a preparation for #42850, #42854 and #42989.

Testing Instructions

Codereview

Link to documentations

Please select:

• [ ] Documentation link for docs.joomla.org:

• [ ] No documentation changes for docs.joomla.org needed

• [ ] Pull Request link for manual.joomla.org:

• [ ] No documentation changes for manual.joomla.org needed