Docker for Mac finally supports IPv6 in general availability. It's time
to add IPv6 to our suite of integration tests.
The thinking behind this PR is try and not slow down CI much, if at all,
by testing IPv6 side-by-side with the existing IPv4 tests.
More comprehensive testing is being developed in #10131 that will test
things like IPv4-in-6 relaying, client / gateway IP stack mismatches,
and so forth.
Closes#5063, supersedes #5850
Other refactors and changes made as part of this:
- Adds the ability to disable DNS control on Windows
- Removes the spooky-action-at-a-distance `from_env` functions that used
to be buried in `tunnel`
- `FIREZONE_DNS_CONTROL` is now a regular `clap` argument again
---------
Signed-off-by: Reactor Scram <ReactorScram@users.noreply.github.com>
Is this worth it?
```[tasklist]
### Before merging
- [x] Double-check docs and ask Jamil to review
- [x] Would need Brian to review the terraform thing
- [x] Make sure Docker compat isn't broken for existing users (shouldn't be, the image is still just `client`)
- [x] Decide whether compatibility tests need to pass (if something breaks after merge we can revert this)
```
For tests it doesn't hurt, but this will be used as a template for the
systemd service we ship to production, and that can't have the ID there.
So I'm also cleaning up a few other problems I noticed:
- I wanted to split the service files as part of #4531, so that the GUI
Client and headless Client can have separate sandbox rules. e.g, the
headless Client won't be allowed to create Unix domain sockets
- I'm punting more things to systemd, which allows us to tighten down
the sandbox further, e.g. creating `/var/lib/dev.firezone.client` and
`/run/dev.firezone.client` for us
- Closes#4461
---------
Signed-off-by: Reactor Scram <ReactorScram@users.noreply.github.com>
