As a user I want to review the activity of my account so that I can see who mentioned or replied to me or what is the latest activity on the spaces I follow

Acceptance criteria

We merge activity and notifications under one section called Activity.
When clicking the bell icon on the top right, it opens a side panel.
There are 2 sections:
1. @toyou (what is notifications today)
2. All updates (what is feed today)

By default it shows notifications where the user is mentioned or replied:

When user taps one notification the related document or paragraph will be open in the center for context
In this section user can see all or just unread (as it is now)
In this section user can mark all as read (as it is now)
In this section user can tap the notifications settings (the current UX needs to be improved).
- There are 2 options: user already accepted getting email notifications when created account ot not. In these dialogs we need to contemplate both options and allow user to add email or change it.

User can expand the Activity panel to see it full screen. In this case, will lose context of the document.
UI related, the name of the document is visually more differentiated from the action (mentioned, replied...)

We need to optimized the number of notification, sometimes for 1 actions there are 2 notifications (see example).

2. All updates

Updates shows latest activity on the spaces User joined
UI related: I proposed from what we currently have:
- Distinguish better where is the activity happening, highlighting the element in green
- When the comments is on a document do not show the card preview has we do now
- When comments are on media, make images and videos preview smaller and expand when clicking on them.