Add user notes on accounts (#14148)

* Add UserNote model

* Add UI for user notes

* Put comment in relationships entity

* Add API to create user notes

* Copy user notes to new account when receiving a Move activity

* Address some of the review remarks

* Replace modal by inline edition

* Please CodeClimate

* Button design changes

* Change design again

* Cancel note edition when pressing Escape

* Fixes

* Tweak design again

* Move “Add note” item, and allow users to add notes to themselves

* Rename UserNote into AccountNote, rename “comment” Relationship attribute to “note”

config/routes.rb

@@ -430,6 +430,7 @@ Rails.application.routes.draw do
 
         resource :pin, only: :create, controller: 'accounts/pins'
         post :unpin, to: 'accounts/pins#destroy'
+        resource :note, only: :create, controller: 'accounts/notes'
       end
 
       resources :lists, only: [:index, :create, :show, :update, :destroy] do