* Adds logical deletes to shared channel remotes and remote clusters
Instead of physically deleting the shared channel remote and remote
clusters records when a channel is unshared, a remote uninvited or a
remote cluster is deleted, now those have a logical `DeleteAt` field
that is set.
This allows us to safely restore shared channels between two remote
clusters (as of now resetting the cursor without backfilling their
contents) and to know which connections were established in the past
and now are severed.
* Delete the index in remoteclusters before adding the new column
* Fix bad error check
* option for auto inviting plugin to all shared channels.
* auto-invite remotes to shared channels when flag set
* fix unit test
* immediately ping new remotes; fix unique siteurl bug
* make i18n-extract
* fix translations
* plugin hooks for file attachments
* hook for profile image sync
* fix profile image sync
* fix unit test
---------
Co-authored-by: Mattermost Build <build@mattermost.com>
It was a good decision in hindsight to keep the public module as 0.x
because this would have been a breaking change again.
https://mattermost.atlassian.net/browse/MM-53032
```release-note
Changed the Go module path from github.com/mattermost/mattermost-server/server/v8 to github.com/mattermost/mattermost/server/v8.
For the public facing module, it's path is also changed from github.com/mattermost/mattermost-server/server/public to github.com/mattermost/mattermost/server/public
```
