Remove release channel from Zed URLs (#8863)

Also adds a new command `cli: Register Zed Scheme` that will cause URLs
to be opened in the current zed version, and we call this implicitly if
you install the CLI

Also add some status reporting to install cli

Fixes: #8857



Release Notes:

- Added success/error reporting to `cli: Install Cli`
([#8857](https://github.com/zed-industries/zed/issues/8857)).
- Removed `zed-{preview,nightly,dev}:` url schemes (used by channel
links)
- Added `cli: Register Zed Scheme` to control which zed handles the
`zed://` scheme (defaults to the most recently installed, or
the version that you last used `cli: Install Cli` with)

crates/gpui/src/app.rs

@@ -566,6 +566,14 @@ impl AppContext {
         self.platform.open_url(url);
     }
 
+    /// register_url_scheme requests that the given scheme (e.g. `zed` for `zed://` urls)
+    /// is opened by the current app.
+    /// On some platforms (e.g. macOS) you may be able to register URL schemes as part of app
+    /// distribution, but this method exists to let you register schemes at runtime.
+    pub fn register_url_scheme(&self, scheme: &str) -> Task<Result<()>> {
+        self.platform.register_url_scheme(scheme)
+    }
+
     /// Returns the full pathname of the current app bundle.
     /// If the app is not being run from a bundle, returns an error.
     pub fn app_path(&self) -> Result<PathBuf> {