Group of contributors to integrate communities like CaptainFact

**Describe the feature/improvement**
Several contributors can be attached to community
This community is more efficient to answser to question and make contributions.

##FEATURES
**Followers**
You can follow a community. If you follow a community you see all of it bubbles.

**Contributions on behalf of the community**
It's a community, each of its accepted member by the admin is able to post and answer on behalf of the community.
Of course each member can still post and answer on his own name.

**Questions :**
- A question sends automatically a mail to each member of the community
- Answers of members are automatically relayed by the community .

**Reviewers option**
- A Reviewer status option can be added as condition to publish.
- On reviewers can publish contribution. Others members can only submit a contribution.
- If answer feature exists, same rules are applied to answers.

**Target user**
CaptainFact
Le Même en Mieux team and their friends ^^
Ethikdo partners ? Ethikdo community (?)
Political communities during next presidentielles (?)

**Fill in the following areas if you have the time...**

**User stories**
How will the user experience this feature/improvement?
1. The user can click a button in [e.g., the extension]
2. User then sees a screen that says [something]
3. ...

**Technical implementation notes**
Any ideas you have about how this could be implemented.

**Additional context**
- Needs more need study (for example with Saptainfact community)
- I was wondering if this features need new extension design with wider space. Probably not, but have to see it more in details.