Refactor: Check server messages in client's message handler

[Phixyn]

Pull Request Submission

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Description

Give a short and brief description of the pull request. Add a screenshot if appropriate and helpful. Changes can be listed in the next section.

Updates the server message payloads to include a type and wrap the content in a content object. Updates the client to handle these new message formats, as well as the error messages sent by the server.

Closes #46.

Changes

List the changes made.

• Updated all server messages to include a "type" string
• Updated all server messages with a "content" object
• Updated client to handle new message format
• Updated client to log server error messages to console
• Updated client to handle SyntaxError for JSON.parse on the onmessage handler

Breaking Change?

Will these changes cause existing functionality to not work as expected? Will contributors be able to run the project after these changes are merged, without needing to take any additional steps?

• [x] Please tick if this is a breaking change and describe why below

Client-server communication protocol update.

Changes were made to the contents and structure of messages sent by the server. This PR updates the client accordingly. After merging this PR, no further action is needed to address the breaking change.

Merging Checklist

Lastly, before merging we need to make sure that these are done.

• [x] Project builds and runs
• [x] All changes were tested
• All tests are up-to-date N/A
• All tests pass N/A
• [x] Code style follows current style guide
• [x] Code documentation is up-to-date
• [x] Project documentation is up-to-date