be_success is deprecated and will be removed in Rails 6.

This was used for the old post fetching

Related to diaspora/diaspora_federation#31

closes #7223

closes #7085

* Adds a new metadata helper and methods to PostPresenter to have metas on post pages.

* Adds tests to post controller to check correctness of metas

* Add methods to PersonPresenter to have metas on profile pages

* Correct meta data helper test

* Update PersonPresenter, add test to PeopleController

* Creates TagPresenter. Display tag metas on tag index page

* Updata meta data helper spec

* Not displaying bio as the description meta on profile page for now. Privacy concerns to be cleared.

* Set meta info as hashes in presenters

* Move original hardcoded metas info to config/defaults.yml

* metas_tags include by default the general metas, update views

* Update code style, clean views

* Renames TagPresenter StreamTagPresenter, updates TagController spec

* Add a default_metas entry to diaspora.yml.example

* Align metas hash in presenters, refactor meta data helper

* Use bio as description meta if user has a public profile

* Rename StreamTagPresenter to TagStreamPresenter

move it to Diaspora::Federation::Entities and use it in some tests, but most of the tests can be removed later.

* move presenters back to controllers, this is view-logic
* use PostService in CommentService
* remove iframe route, this is not used anymore
* id/guid limit at 16 chars, hex(8) is 16 chars long

closes #6533

closes #6490

Squashed commits:

[ada0f09] Remove favorites from Posts table

closes #6208

deletes ActivityStream model and all it's references

update migration with the without_protection option to disable mass assignment protection

and tries to access a show page of a non-public post

This reverts commit c52342b7.

Lazily load post interactions on show page
hella refactorz

and comment presenter

clean up controller

include an iframe route, for posts, and a magic body padding removal for screens with small widths (for some reason, smaller than 770

Verify that the correct layout is rendered (rather than no layout
at all) in the mobile UI single post view.

This is a test I forgot to write at 5am when I was so excited about
having the mobile UI working on my Blackberry again (bad me!), so
here it is before it slips my mind. 

This tests the change made to posts_controller in 6abe7182