[web] Subscribe and unsubscribe from feed feed.url_updated notification type

[davidgamez]

Description

Affer this issue is implemented

• Users are able to: subscribe and unsubscribe feed.url_updated notification type
• The UI Global Notification Settings modal and the Global Notification Preferences settings only shows the option:
  • text: Feed URL updated
  • tool tip: Fired when a feed URL changes in-place or a feed is deprecated and redirected to another feed.
• "Frequency of Notification" option is not shown
• At the Account's Notification screen, the user is able to pause, resume and unsubscribe from feed.url_updated notifications.

[Alessandro100]

Tasks

• In feed detail page, implement subscribed endpoint (UI there currently being mocked)
• In feed detail page (if they are subscribed to the feed) allow them to (pause, resume and unsubscribe) to the feed
• Add the notification list in the notification account settings page
• In the notification account setting page, allow the user to (pause, resume and unsubscribe) from each notification
• In the notification account setting page remove all the unsupported notification settings