Create daemons on initial site provisioning

[prashank25]

This PR allows creating daemons on forge when provisioning a new site.

You can create a single or multiple daemons the same way as queue workers. The user and directory is set to the same ones used on the site, a reasonable default I think.

env:
  FORGE_DAEMONS: php artisan horizon

or

env:
  FORGE_DAEMONS: |
    php artisan horizon
    php artisan pulse:check
    custom.sh --directory=/path/to/script --user=forge --processes=1 --startsecs=10 --stopwaitsecs=60 --stopsignal=SIGTERM

If the command you need to run has arguments of its own, you can single or double-quote the entire command.

env:
  FORGE_DAEMONS: "something-to-run --argument=value" --directory=/path/to/script --user=forge

---

Handling of teardown process.

When in user isolation mode, daemon removal happens by deleting all daemons that are running as the user used for the site.

In all cases, daemons are deleted if their directory falls within the site currently being teardown-ed.

After all that, any remaining daemons are deleted based on the env variable set by the user. So it is recommended to add the same env value for FORGE_DAEMONS for teardown workflow as well. Would ask you to review the code for teardown carefully. Thanks.

---

And finally some concerns

The inertia pipeline steps seem redundant for the most part and can simply be replaced with php artisan inertia:start-ssr in the FORGE_DAEMONS. Additionally, it adds inertia:stop-ssr to the deployment script, which seems out of scope to do automatically. The user still needs to write their deployment script anyway, and they should add the daemon-killing command to their script, as suggested by the documentation for those libraries.

That being said, I have not made any changes to inertia as that would be a breaking change.

I will be submitting another PR to fix the handling of user isolation in the scheduler job and inertia daemon creation. Since at the moment it's hard coded to forge.

Apologies for the wall of text 😞

[mehrancodes]

@prashank25, everything looks great - just one small issue when tearing down the site.

[mehrancodes]

Nice work here, @prashank25! Thank you!