* Added a less accurate ChannelMembers fallback that is used if export period occurs before MessageExport was enabled
* Fixed test names
* Improved testing
* Made hasDataFromBefore() a little less strict
* Fixed the test to cleanly truncate the ChannelMemberHistory table without exposing the db via the interface
* Renamed a function for better clarity
* Binary logic is hard
* Changed the channel member history purge function to match pattern established by other data retention purge methods
* Simplifying the channel member history store and associated tests
* Regenerating mocks
* Using a constant
* Created message export scheduled task
* Added CLI command to immediately kick off an export job
* Added email addresses for users joining and leaving the channel to the export
* Added support for both MySQL and PostgreSQL
* Fixing gofmt error
* Added a new ChannelMemberHistory store and associated tests
* Updating the ChannelMemberHistory channel as users create/join/leave channels
* Added user email to the message export object so it can be included in the actiance export xml
* Don't fail to log a leave event if a corresponding join event wasn't logged
* Adding copyright notices
* Adding message export settings to daily diagnostics report
* Added System Console integration for message export
* Cleaned up TODOs
* Made batch size configurable
* Added export from timestamp to CLI command
* Made ChannelMemberHistory table updates best effort
* Added a context-based timeout option to the message export CLI
* Minor PR updates/improvements
* Removed unnecessary fields from MessageExport object to reduce query overhead
* Removed JSON functions from the message export query in an effort to optimize performance
* Changed the way that channel member history queries and purges work to better account for edge cases
* Fixing a test I missed with the last refactor
* Added file copy functionality to file backend, improved config validation, added default config values
* Fixed file copy tests
* More concise use of the testing libraries
* Fixed context leak error
* Changed default export path to correctly place an 'export' directory under the 'data' directory
* Can't delete records from a read replica
* Fixed copy file tests
* Start job workers when license is applied, if configured to do so
* Suggestions from the PR
* Moar unit tests
* Fixed test imports
* Add column to UserAccessTokens table
* PLT-7794 Add user access token enable/disable endpoints
* replaced eliminated global variable
* updates to user_access_token_store and upgrade.go
* style fix and cleanup
* fix in:channel search when channel name/displayname includes `-`
* fix failing test in PostgreSQL
* add lowercase indexes of channel's name and displayname to postgresql, and add unit tests
* Return viewed at times in view channel API response
* Updated transaction to read and write once
* Remove transaction and only update if new value greater than older
* PLT-7202: Switch user search to LIKE queries to avoid fulltext pitfalls.
* Add 2 char name unit test.
* Escape underscores properly.
* Add more tests and fix * handling.
* Make search/indexes case insensitive for postgres.
