This reverts commit 20780a1eee.
* SECURITY: re-adds accidentally reverted commit:
03d26cd6: ensure embed_url contains valid http(s) uri
* when the merge commit e62a85cf was reverted, git chose the 2660c2e2 parent to land on
instead of the 03d26cd6 parent (which contains security fixes)
The main thrust of this PR is to take all the conditional checks based on the `enable_bookmarks_with_reminders` away and only keep the code from the `true` path, making bookmarks with reminders the core bookmarks feature. There is also a migration to create `Bookmark` records out of `PostAction` bookmarks for a site.
### Summary
* Remove logic based on whether enable_bookmarks_with_reminders is true. This site setting is now obsolete, the old bookmark functionality is being removed. Retain the setting and set the value to `true` in a migration.
* Use the code from the rake task to create a database migration that creates bookmarks from post actions.
* Change the bookmark report to read from the new table.
* Get rid of old endpoints for bookmarks
* Link to the new bookmarks list from the user summary page
* This PR implements the scheduling and notification system for bookmark reminders. Every 5 minutes a schedule runs to check any reminders that need to be sent before now, limited to **300** reminders at a time. Any leftover reminders will be sent in the next run. This is to avoid having to deal with fickle sidekiq and reminders in the far-flung future, which would necessitate having a background job anyway to clean up any missing `enqueue_at` reminders.
* If a reminder is sent its `reminder_at` time is cleared and the `reminder_last_sent_at` time is filled in. Notifications are only user-level notifications for now.
* All JavaScript and frontend code related to displaying the bookmark reminder notification is contained here. The reminder functionality is now re-enabled in the bookmark modal as well.
* This PR also implements the "Remind me next time I am at my desktop" bookmark reminder functionality. When the user is on a mobile device they are able to select this option. When they choose this option we set a key in Redis saying they have a pending at desktop reminder. The next time they change devices we check if the new device is desktop, and if it is we send reminders using a DistributedMutex. There is also a job to ensure consistency of these reminders in Redis (in case Redis drops the ball) and the at desktop reminders expire after 20 days.
* Also in this PR is a fix to delete all Bookmarks for a user via `UserDestroyer`
