Some pages aren't translation-ready

[DeeDeeG]

From #413:

When looking at @stardust66's PR over at Intimaria/refugerestrooms:#1, I noticed that we have some pages that aren't translation-ready.

We need to update:

• the "splash" page (homepage),
• the Contact page,
• the search results page,
• the nav bar (at the top)
• the footer
• search bar buttons
• ARIA labels (probably)
• and if somehow possible, the API documentation page.

Making them "translation-ready" would involve taking "hard-coded" sentences and phrases and moving them into a [something].en.yaml file, then updating the actual pages to refer to translation strings in place of hard-coded phrases. In other words, expand the existing translation system to also cover the pages I mentioned.

Solving this helps us to progress with #396 and ensure we can more-comprehensively complete #413

[DeeDeeG]

The API documentation page still isn't translated, since all the text for that is hard-coded into a javascript file.

And looking forward, if we add new text to the app, said text should use the i18n API.

But this is basically done, so I'm closing this! Woo!