Even if we aren't codesigning, things like the `package` target expect
to be able to depend on `notarize` (and thus implicitly sign ->
assemble) to require a built package.
Also add a `-UNSIGNED` into the built dmg filename.
- Add the version number into the .dmg filename
- Set the lokinet icon on the .dmg. This is done via a swift program
because all the Apple CLI tools to do this are deprecated.
The macOS PR that was merged accidentally dropped a cmake option that
result in the extension's provisioning profile not getting copied into
place (but was working locally because I was using a build dir where the
variable was still set). This restores the option to fix the
codesigning.
