Add official tag to endpoints

[emmambd]

Describe the problem

See above

Proposed solution

Official field should be in API responses

Alternatives you've considered

No response

Additional context

No response

[davidgamez]

Tasks:

• add the official tag to feed, feeds and search endpoints
• add official as part of the filters to all feed(s)

[cka-y]

Needs #821 to be merged