Add the ability to edit remote directories over SSH (#14530)

This is a first step towards allowing you to edit remote projects
directly over SSH. We'll start with a pretty bare-bones feature set, and
incrementally add further features.

### Todo

Distribution
* [x] Build nightly releases of `zed-remote-server` binaries
    * [x] linux (arm + x86)
    * [x] mac (arm + x86)
* [x] Build stable + preview releases of `zed-remote-server`
* [x] download and cache remote server binaries as needed when opening
ssh project
* [x] ensure server has the latest version of the binary


Auth
* [x] allow specifying password at the command line
* [x] auth via ssh keys
* [x] UI password prompt

Features
* [x] upload remote server binary to server automatically
* [x] opening directories
* [x] tracking file system updates
* [x] opening, editing, saving buffers
* [ ] file operations (rename, delete, create)
* [ ] git diffs
* [ ] project search

Release Notes:

- N/A

---------

Co-authored-by: Piotr Osiewicz <24362066+osiewicz@users.noreply.github.com>

crates/paths/src/paths.rs

@@ -224,26 +224,28 @@ pub fn default_prettier_dir() -> &'static PathBuf {
     DEFAULT_PRETTIER_DIR.get_or_init(|| support_dir().join("prettier"))
 }
 
+/// Returns the path to the remote server binaries directory.
+pub fn remote_servers_dir() -> &'static PathBuf {
+    static REMOTE_SERVERS_DIR: OnceLock<PathBuf> = OnceLock::new();
+    REMOTE_SERVERS_DIR.get_or_init(|| support_dir().join("remote_servers"))
+}
+
 /// Returns the relative path to a `.zed` folder within a project.
 pub fn local_settings_folder_relative_path() -> &'static Path {
-    static LOCAL_SETTINGS_FOLDER_RELATIVE_PATH: OnceLock<&Path> = OnceLock::new();
-    LOCAL_SETTINGS_FOLDER_RELATIVE_PATH.get_or_init(|| Path::new(".zed"))
+    Path::new(".zed")
 }
 
 /// Returns the relative path to a `settings.json` file within a project.
 pub fn local_settings_file_relative_path() -> &'static Path {
-    static LOCAL_SETTINGS_FILE_RELATIVE_PATH: OnceLock<&Path> = OnceLock::new();
-    LOCAL_SETTINGS_FILE_RELATIVE_PATH.get_or_init(|| Path::new(".zed/settings.json"))
+    Path::new(".zed/settings.json")
 }
 
 /// Returns the relative path to a `tasks.json` file within a project.
 pub fn local_tasks_file_relative_path() -> &'static Path {
-    static LOCAL_TASKS_FILE_RELATIVE_PATH: OnceLock<&Path> = OnceLock::new();
-    LOCAL_TASKS_FILE_RELATIVE_PATH.get_or_init(|| Path::new(".zed/tasks.json"))
+    Path::new(".zed/tasks.json")
 }
 
 /// Returns the relative path to a `.vscode/tasks.json` file within a project.
 pub fn local_vscode_tasks_file_relative_path() -> &'static Path {
-    static LOCAL_VSCODE_TASKS_FILE_RELATIVE_PATH: OnceLock<&Path> = OnceLock::new();
-    LOCAL_VSCODE_TASKS_FILE_RELATIVE_PATH.get_or_init(|| Path::new(".vscode/tasks.json"))
+    Path::new(".vscode/tasks.json")
 }