Limit number of activity feed events created by a single push

@jacobvosmaer-gitlab wrote in https://gitlab.com/gitlab-org/gitlab-ce/issues/65804#note_201989032:

if someone pushes 20,000 tags, do we really want to create 20,000 activity feed events?

@stanhu responded in https://gitlab.com/gitlab-org/gitlab-ce/issues/65804#note_202085181

Probably not. We could probably just do what we do with large commits and just insert a single message that says, Pushed N tags.

Expected outcome

Don't create multiple events if the number of branches/tags are more than 3. Create a single event instead with the message Pushed N tags or Pushed N branches.