Migrate to the new REST API

[oscfdezdz]

https://extensions.gnome.org/api/docs/

It has existed for more than a year now and we have to switch to it if we want to add information that was added relatively recently such as session modes, version name or anything else that will be added in the future.

The legacy API does not accept further changes, see https://gitlab.gnome.org/Infrastructure/extensions-web/-/merge_requests/174#note_1926296.

The new API has endpoints that will allow us to add new features such as login or register among others. Although there are some fields that are missing or I cannot find that we will have to add:

• Homepage URL
• Donation URLs
• Version name
• Session modes

There do not seem to be any endpoints for comments either, so it will be the only request that will not have to be changed for the time being.

We cannot directly filter by shell version with neither /extensions/ nor /extensions/search/{query}/ endpoints.