[lib] introduce addCommunityActionType

Summary:
This diff introduces the addCommunityActionType which will be used in the community reducer

Linear task: https://linear.app/comm/issue/ENG-6578/introduce-add-a-community-to-the-community-store-action

Depends on D11164

Test Plan: flow + functionality will be tested in very next diff

Reviewers: atul, inka, kamil

Reviewed By: atul, kamil

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D11165