lsp: Remove reinstall, update config (#18318)

Release Notes:

- Fixed overriding the path of a language server binary for all language
servers. `{"lsp":{"<lsp-name>":{"binary":{"path": "_"}}}}` will now work
for all language servers including those defined by extensions.
- (breaking change) To disable finding lsp adapters in your path, you
must now specify
`{"lsp":{"<lsp-name>":{"binary":{"ignore_system_version": true}}}}`.
Previously this was `{"lsp":{"<lsp-name>":{"binary":{"path_lookup":
false}}}}`. Note that this setting still does not apply to extensions.
- Removed automatic reinstallation of language servers. (It mostly
didn't work)

---------

Co-authored-by: Mikayla <mikayla@zed.dev>

crates/lsp/src/lsp.rs

@@ -64,6 +64,15 @@ pub struct LanguageServerBinary {
     pub env: Option<HashMap<String, String>>,
 }
 
+/// Configures the search (and installation) of language servers.
+#[derive(Debug, Clone, Deserialize)]
+pub struct LanguageServerBinaryOptions {
+    /// Whether the adapter should look at the users system
+    pub allow_path_lookup: bool,
+    /// Whether the adapter should download its own version
+    pub allow_binary_download: bool,
+}
+
 /// A running language server process.
 pub struct LanguageServer {
     server_id: LanguageServerId,