feat(regions): include income groups

[marcelgerber]

Fixes #3517.

Goes together with https://github.com/owid/cloudflare-workers/pull/21.

TODOs

• Add a custom tooltip for the new entity selector, that links to https://ourworldindata.org/grapher/world-bank-income-groups somewhere.
  • Probably use DoDs for this use case
  • If so, then also provide a fix for Links to Graphers don't work inside DoDs #3217

[owidbot]

Quick links (staging server):

Site	Admin	Wizard

Login: ssh owid@staging-site-update-regions-income-groups

• Site-screenshots: https://github.com/owid/site-screenshots/compare/update-regions-income-groups
• SVG tester: https://github.com/owid/owid-grapher-svgs/compare/update-regions-income-groups

SVG tester:

Number of differences (default views): 0

Number of differences (all views): 0

Edited: 2024-05-06 12:53:18 UTC
Execution time: 1.20 seconds

[github-actions]

This PR has had no activity within the last two weeks. It is considered stale and will be closed in 3 days if no further activity is detected.