[MM-55726] Create batch report worker, add batch report job for exporting users to CSV (#25832)

* Split out migration logic and create generic BatchWorker

* WIP

* WIP

* POC batch reporting

* Oops

* Job hookup

* Working export to file

* PR feedback

* Merge'd

* Fix error handling

* Add API to start report, translations, couple fixes

* Add DMs to send reports to users

* Merge'd

* Update types

* A bit of cleanup

* Some fixes

* Add missing API doc

* PR feedback

* Fix generated

* Fix bug with post creation

* PR feedback

* Add some tests

* PR feedback

* Fix lint

* Some test changes

* Fix tests

* Add comment to explain why we forcibly stop

* Rework of some tests

* Batch report test

* Restrict batch exports to Pro and Enterprise licenses

* Fix erroneous comment

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/public/model/user.go

@@ -1015,7 +1015,6 @@ func (u *User) EmailDomain() string {
 }
 
 type UserPostStats struct {
-	LastLogin    int64  `json:"last_login_at,omitempty"`
 	LastStatusAt *int64 `json:"last_status_at,omitempty"`
 	LastPostDate *int64 `json:"last_post_date,omitempty"`
 	DaysActive   *int   `json:"days_active,omitempty"`