Add Notification collection and APIs to retrieve and delete Notifications

[Sebastian-Webster]

The Notification collection would have a TTL index so notifications would only be stored for 7 days after they are created.

Notification documents would be created for all notifications EXCEPT chat related notifications.

The notifications I can currently think of are:

• Upvoted post or comment
• Someone followed / requested to follow you
• Someone commented on a post of yours

A notification document could have one of these two:

1. profilePublicId - For notifications to do with someone following or requesting to follow you (allows the frontend to navigate to that user's profile)
2. postId & postFormat - For notifications related to comments, comment upvotes, and post upvotes

Schemas to be created:

1. Notification

Notification Schema Fields:
userId - ObjectId
profilePublicId - String
postId - ObjectId
postFormat - String
dateCreated - Date
text - String

New APIs to be created:

1. GET temp/notifications
2. POST temp/deletenotification (takes notificationId in body)
3. POST temp/clearnotifications

APIs to be modified:

1. temp/deleteimage
2. temp/deletepoll
3. temp/deletethread
4. temp/deleteaccount
5. temp/toggleFollowOfAUser
6. temp/deletecomment
7. temp/voteoncomment
8. temp/voteonpost
9. temp/removevoteoncomment
10. temp/removevoteonpost
11. temp/blockaccount