* image proxy support
* go vet fix, remove mistakenly added coverage file
* fix test compile error
* add validation to config settings and documentation to model functions
* add message_source field to post
* add post' root ID to apiv4 addChannelMember to render added user (as system post) at RHS
* add check to post_root_id parameter
* add AddChannelMemberWithRootId function for backward compatibility
* 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-7206: UI changes. Removed last user in channel loophole, refactored code to clean it up, added differentiated support for public and private channels, added unit tests. Still need to implement server-side checks
* PLT-7206: All helper methods in channel_utils.jsx now accept the same three boolean variables in the same order and use the same boolean logic to check their values.
* PLT-7206: Added unit tests for showManagementOptions(...)
* PLT-7206: Fixed test case descriptions
* Added unit tests for showCreateOption(...)
* PLT-7206: Added unit tests for canManageMembers(...)
* PLT-7206: Removed last person in channel loophole from server-side code
* PLT-7206: Reverted config.json
* PLT-7206: Fixed double negatives in unit test names
* PLT-7206: PR feedback - Removed confusing comment and unused variable
* channel delete option is hidden from the menu unless there is appropriate permissions as set in the policy page
* apply to public channel only and add restriction to API layer
* updated channel deletion
* Revert "PLT-5765 Passed SiteURL to SendNotifications (#5705)"
This reverts commit a8e68bd890.
* Removed automatic configuration of SiteURL
* Reverted unintentional config changes
* Updated help text
* Added link to docs in Site URL warning
* Fixed merge conflict
* Add v4 endpoint for getting the channels on a team for a user
* Implement PUT /channels/{channel_id}/patch endpoint for APIv4
* Implement POST /teams/{team_id}/channels/search endpoint for APIv4
* Update permission check
* Implement POST /channels/members/{user_id}/view endpoint for APIv4
* Implement PUT /channels/{channel_id}/members/{user_id}/roles endpoint for APIv4
* Implement DELETE /channels/{channel_id}/members/{user_id} endpoint for APIv4
* implement get channels endpoints and updated drivers and unittests
* removed channel deletion on tear down, removed manage permission on get channels endpoints, and updated utils to add constant channel length
* added constants for user, team and channel length, updated context to use the model functions
* make sure team name length should be less than the minimum length and revert underscore to team name validity
* changed post test condition from notfound to unauthorized
* Implement GET /channels/{channel_id}/members
* Implement GET /channels/{channel_id}/members/{user_id} endpoint for APIv4
* Implement /users/{user_id}/teams/{team_id}/channels/members endpoint for APIv4
* Fix unit test
