feat: plugins can now be spawned as Workers

[gentlementlegen]

Resolves #39

[gentlementlegen]

Tests seem to be failing due to empty environment variables during the tests https://github.com/ubiquity/ubiquibot-kernel/actions/runs/9149319076/job/25152816695?pr=42#step:5:7 which I cannot fix myself.

[0x4007]

@rndquu youre admin please facilitate

[rndquu]

@gentlementlegen

Check this workflow

How it works right now:

1. PR is opened
2. The development branch is checked out here (not the PR branch because the workflow is running on pull_request_target)
3. Tests are run against the development branch

If here we change the code to checkout the PR branch using pull_request_target then any fork will have access to these env variables.

So right now this workflow is literally 1 line away from leaking secrets.

There are viable 2 options:

1. Refactor tests and mock everything in a way that we wouldn't need to provide any env vars
2. Keep using this workflow with pull_request_target, checkout the PR branch here, hardcode env variables and use some dummy values that are used only for testing

[gentlementlegen]

@rndquu will be mocking as we cannot have dummy values since it tries to reach a real endpoint.

[gentlementlegen]

Changes in this PR

• plugins can now accept urls to endpoints, by setting the url value inside plugins instead of a GitHub Action
• tests are triggered on pull_request with mocked values
• the project is automatically deployed on pushes in the main branch and also updates the secrets in Cloudflare with the ones from GitHub to avoid manually setting them (requires WEBHOOK_PROXY_URL, WEBHOOK_SECRET, APP_ID, PRIVATE_KEY to be set)

Test still expected to fail for pull_request_target, successful pull_request test here

[whilefoo]

we can merge this, right?

[gentlementlegen]

@whilefoo was waiting for second validation but if you're good with it for sure