Allow users to enable/disable Headscale and VPN access

[Tpuljak]

Is your feature request related to a problem? Please describe.
Currently, Daytona always starts a Headscale server which is used to manage the VPN that enables and controls access to workspaces and projects. While the VPN provides a layer of security when connecting to projects, it is also an additional point of failure and latency.

Describe the solution you'd like
We should allow users to enable/disable the Headscale server and allow direct connection to workspaces and projects. If the user disables Headscale, we should provide an alternative secure option to connect to workspaces and projects.
This option could be direct SSH access which would require SSH key authentication but we can discuss other approaches as well.
The important thing is that we maintain the same flow and UX when Headscale is enabled or disabled.

Additionally, since we rely on Headscale for port forwarding, the alternative that we choose must be able to provide that as well.