[FRONTEND] Write custom hook to recieve SSE (Server Sent Events)

[bcho892]

Is your feature request related to a problem? Please describe.

Because of the new endpoint created in #662 we will now need to have a way to consume the events on the frontend. For our project this will consist of two steps:

1. Create a generic hook that allows creation of an EventSource for a given endpoint and appropriately attach callbacks or if a request body is required a library such as fetchEventSource would be required
2. Use that implementation to create a hook that allows us to constantly stream event signup numbers on the front end

[!NOTE] You should not be hard-coding the base url for the endpoint, instead look into process.env to get the appropriate base URL

[!WARNING] There should be a way for us to close the connection if needed

BEFORE MERGING

• [ ] Storybooks created where possible
• [ ] Tested with nock if data fetching
• [ ] Tests written for critical interactions
• [ ] PR Reviewed (For non-trivial changes)
• [ ] Changes tested after rebasing on master or merging in master (hint: git fetch origin master:master, then git rebase master or git merge master)
• [ ] All required PR checks passing

[jeffplays2005]

Not planned