* feat: Add connection_timeout and troubleshooting_url to agent
This commit adds the connection timeout and troubleshooting url fields
to coder agents.
If an initial connection cannot be established within connection timeout
seconds, then the agent status will be marked as `"timeout"`.
The troubleshooting URL will be present, if configured in the Terraform
template, it can be presented to the user when the agent state is either
`"timeout"` or `"disconnected"`.
Fixes#4678
* chore: Separate the provisionerd server into it's own package
This code should be thoroughly tested now that we understand the abstraction.
I separated it to make our lives a bit easier for external provisioner daemons
as well!
* Add tests
* Add workspace builds
* Add test for workspace resources
