Internationalize the About page

[wbazant]

To display the About page in various languages, we need to move the text out of HTML and into the locale file, and use the same keys as on the live site.

Here's the live site with i18n_viz switched on:
https://fallingfruit.org/about?c=forager%2Cfreegan&locale=en&i18n_viz=1

See #488 and especially Ethan's guidance for translations at #488 (comment)

[mpastoring]

Hey @wbazant, I can help with this issue. Could you please assign me? Happy to help.

[ezwelty]

@manuelpastorringuelet Welcome and thanks for offering to help. I've assigned you the issue.