Deliver match-start notifications for users not actively viewing the match/lobby page

[jiyeongchloe]

Goals: According to the user stories, when a player joins a lobby but is not actively viewing the specific lobby page at the start of a match, they are prompted to join the match from wherever they are at. While the specific lobby page changes to display the join match button, we do not have functionalities to notify users who are not actively viewing the detail page. We need to speak to the Users team (who has a framework for notification systems) to display match-start notifications for users who have joined a lobby.

Deliverables:

• Meeting notes from contacting the Users team about how their notification system might be used for matches/lobby-purposes
• Pull Request