Add serve command

[OleksandrRoshchuk]

No description provided.

[gabesullice]

I started to review this and encountered the HTTPS error that @OleksandrRoshchuk mentioned to me in Slack (screenshot below).

The reason that HTTP is required is because local.applura.app uses the .app TLD, which makes HTTPS mandatory.

I suggested the mkcert program as a convenient way to generate and trust a locally generated certificate. But it looks like the node.js version of the mkcert program does not automatically install the root certificate authority that it uses.

We need to either:

1. figure out how to do that in this command
2. consider whether it would be insane to hard-code a valid private key that we personally generate and maintain
3. document how to install and use the standalone mkcert program

1 is most preferable, 2 is acceptable if we're willing to accept the risk, 3 is least preferable because it's the most clunky developer experience.

The risk with #2 is that it could potentially be abused in a phishing attack if:

1. Nobody realized that the domain is local.applura.app instead of somethingelse.applura.app
2. The attacker is able to serve the malicious site from 127.0.0.1 (since that's where the local.applura.app A record points)