The standalone CLI should detect and fall back to using and
system-installed VS Code instance, rather than trying to download zips
and manage its own VS Code instances.
There are three approaches used for discovery:
- On Windows, we can easily and quickly read the register to find
installed versions based on their app ID.
- On macOS, we initially look in `/Applications` and fall back to the
slow `system_profiler` command to list app .app's if that fails.
- On Linux, we just look in the PATH. I believe all Linux installers
(snap, dep, rpm) automatically add VS Code to the user's PATH.
Failing this, the user can also manually specify their installation dir,
using the command `code version use stable --install-dir /path/to/vscode`.
Fixes#164159
- Start separating a "standalone" CLI. This is a little awkward with clap-
derive, but I got it working. Detection of whether the CLI _is_
standalone is still todo.
- Remove the old ad-hoc update code for code-server, and use the update
service instead.
- Fix some of the "permission denied" errors people got while updating
before. We need to rename the old running binary, not just overwrite it.
