Various improvements to Mattermost, Teams, Slack integrations

[albogdano]

• Add a question select dropdown on the "Answer a question" dialog
• Support for threaded notifications (reply notification should be in same thread as question notification message)
• Mark spaces that are linked to chat channels on user profile page
• Add checkboxes to webhook form so we can select what type of content is sent to chat channels as notifications, i.e. "questions only", "questions & answers", "comments only" and "all". ✅ done

[KatteStone]

All these topics will highly improve the MATTERMOST <-> SCOOLD integration. I am looking forward to be able to use these new features.