[parent issue] improve developer experience

[leloykun]

Admin stuff

• Add a branch protection rule that requires at least one approval from a reviewer before merging
• Limit who can review to only the admins or more experienced contributors
• (optional) Make @leloykun an admin

Visibility

• Sync the repo to the #online-judge channel in NOI-PH's Discord server (so we get alerted every time someone submits a pull request or something)

Tests

• Add tests for each component (e.g. web-client & web-server)
• Add github actions that run the tests on pull request / push. Preferably we have separate github actions for web-client & web-server so we can limit which tests we run based on the contents of the PR

Developer Experience

• Add pre-commit hooks
• Add github actions that run linters such as eslint & black and typechecks that get run on pull request / every push
• Add a script that runs web-client / web-server. Perhaps with an interface like ./run.sh client & ./run.sh server

Docs

• Clean up the readmes in web-client & web-server
• Cleanup the tutorials folder (& convert git-workflow-for-code-monkeys-like-me.txt to a readme)
• Add instructions on how to deploy this to the cloud