TWE-47 Move canoncial tags to base template

[JakubMastalerz]

TWE-47

Description of Changes Made

When applied, this PR will apply canonical tags to all pages through the base template instead of applying them to listing templates. Additionally, paginated pages' canonical tags behaviour changes to include the page number.

How to Test

Unit tests

• Added
• Not required

Documentation

• Updated build docs
• Updated editor guidelines (See https://intranet.torchbox.com/torchbox-com-project-docs for the private link, for Torchbox employees only)
• Updated field spec (See https://intranet.torchbox.com/torchbox-com-project-docs for the private link, for Torchbox employees only)
• Not required

Browser testing

• I have tested in the following browsers and environments (edit the list as required)
  • Latest version of Chrome on mac
• Not required

Data protection

• Not relevant
• This adds new sources of PII and documents it and modifies Birdbath processors accordingly

Light and dark mode

• I have tested the changes in both light and dark mode
• The change is not relevant to dark and light mode

Accessibility

• Automated WCAG 2.1 tests pass
• HTML validation passes
• Manual WCAG 2.1 tests completed
• I have tested in a screen reader
• I have tested in high-contrast mode
• Any animations removed for prefers-reduced-motion
• Not required

Sustainability

• Images are optimised and lazy-loading used where appropriate
• SVGs have been optimised
• Performance and transfer of data considered
• If JavaScript is needed alternatives have been considered
• Not required

Pattern library

• The pattern library component for this template displays correctly, and does not break parent templates
• The styleguide is updated if relevant
• Changes are not relevant the pattern library

[helenb]

@nicklee @tm-kn I think we might need to check this in relation to the incoming listing page changes, which update the cannonical urls for the filtered listings.

[JakubMastalerz]

@helenb Just fyi, this work is considered "blocked" for now, as discussed here: https://torchbox.slack.com/archives/C06AQA4D0RX/p1783001032710819