Improve Photos localization

[jonoaldersonwp]

​The photos site only exists on the main dot org site; requests to, e.g., ​https://fr.wordpress.org/photos/ or ​https://de-at.wordpress.org/photos/photo/35161f73a8/ return 404 errors.

This causes some crawling, indexing and reporting issues; especially as we include hreflang hints on these pages.

To address this, we should:

• Remove hreflang hints from Photos pages
• Redirect requests to Rosetta photos patterns to the equivalent URL on the main site

[dd32]

In 12404:

Photo Directory: Disable the hreflang tags, the photo director is not currently localised.

Fixes #6771.