API: give list of rated services

[hugoroy]

I suppose that the API should also offer something like: https://tosdr.org/api/1/ratings.json

for the list of services that are in the database, with their associated Class (A-E or no Class) and their URL.

That way the browser extension only needs to download ratings.json at every startup to get up-to-date data (instead of relying on https://tosdr.org/index/services.json for instance -- which should be deprecated)

TODO

• [x] write the code for the API
• [ ] update the https://github.com/tosdr/browser-extensions
• [ ] document it in src/api.html

[Ryuno-Ki]

This matches pretty well what I asked for in tosdr/tosdr.org#147.

[michielbdejong]

This already exists, see https://tosdr.org/index/ratings.json