Preload enterprise logos and promo images for /shops page

[johansenja]

What? Why?

When visiting https://openfoodnetwork.org.uk/shops, the page load is very slow. Given that this page is linked to from the
CTA above the fold on https://openfoodnetwork.org.uk, it seems ideal that should load quickly.

One of the low-hanging fruits here is to make sure that each of the enterprise's logo and promo_image is preloaded, to avoid n+2 queries:

It's not the most significant performance increase (though I have a few other ones too) - especially when there is caching - but it feels like a sensible thing to do

What should we test?

• Visit /shops page

Release notes

Changelog Category (reviewers may add a label for the release notes):

• User facing changes
• API changes (V0, V1, DFC or Webhook)
• Technical changes only
• Feature toggled

Dependencies

I have some other low-hanging fruit optimisations that I might propose here too (which might also be more significant) but they should be distinct enough to be separate follow-ons

Documentation updates

N/A

[mkllnk]

Thank you! What an excellent contribution. Well done. I'm looking forward to your other optimisations.

[rioug]

Nice one 👍 Thanks for your contribution 🙏