Make userspace networking configurable

[lmagyar]

Note: this is based on / continuation of #196, but I will rebase this PR as required.

Proposed Changes

The currently unreleased #181 dropped userspace networking automatically.

I've merged it into my fork, and 1 user complained, that his host lost all network access (even local 192.168.x.x did not worked). UPDATE: The reason must be that the same subnet is advertised at multiple locations and it caused collision. The PR #201 provides a possible solution for collision, but I think making userspace-networking configurable still makes sense.

This PR makes it configurable, by default the add-on still uses userspace networking, but if somebody adds userspace_networking: false to the configuration, it will drop it and create the tailscale0 interface with all of the dangers of it.

But at least it requires manual intervention and doesn't happen automatically during an add-on update.

Related Issues

[frenck]

I have one of my own test instances that has the same problem (which is the main reason for it not being released yet).

However, I don't think this a solution nor a workaround. In some situations loosing access is problematic and would also prevent one from accessing this workaround. Not all devices used for HA have access to the system terminal.

../Frenck

[lmagyar]

not stale, also multiple PR-s are based on this

[lmagyar]

not stale

[frenck]

Needs #201 first (and a rebase).

[frenck]

but I think making userspace-networking configurable still makes sense.

I'm not sure why? I think we should just drop it fully.

Let's just do it.

../Frenck

[frenck]

Thanks, @lmagyar 👍

../Frenck

[lmagyar]

but I think making userspace-networking configurable still makes sense.

I'm not sure why? I think we should just drop it fully.

Let's just do it.

../Frenck

Yes, I just afraid that turning off userspace networking can mess up configs. Most of the people will not use tailscale0/tunneling I think.