Add MattermostSlashCommands instance integration
As part of &16600 (closed) we need to create instance versions of existing integrations. Create MattermostSlashCommands instance integration, similar to !177125 (merged)
Edited by George Koltsov
As part of &16600 (closed) we need to create instance versions of existing integrations. Create MattermostSlashCommands instance integration, similar to !177125 (merged)