Upgrade from Node 10 to Node 20

[benfrancis]

This PR upgrades the version of Node.js used by WebThings Gateway from version 10 to version 20.

This requires upgrading various npm packages and applying a bunch of TypeScript fixes, and updating the GitHub Action to run using Node.js 20.

TODO:

• Resolve merge conflicts since NetworkManager PR landed
• Figure out why integration tests pass but then the process exits with an error
• Update snap to use Node.js 20
• [ ] Update docker image to use Node.js 20 Going to do this in a follow-up because the Docker image needs other work doing to it as well

[benfrancis]

@tim-hellhake I think this is nearly ready, I just can't figure out why jest is exiting with an error in CI even though all the tests are passing. Any ideas?

[benfrancis]

Finally got the tests to pass!

I'm going to split bb0a1ad out into a separate PR because I don't think it's strictly necessary and I'd like to better understand what we're losing, but otherwise I think this is ready to land.

I intend to keep the full commit history rather than squash them so that we can bisect later if any of these upgrades cause regressions.

[benfrancis]

Ah, it turns out that the deprecated coverage command was also preventing the integration test action from completing successfully after all, so I've added the commit back to remove it.