Add extensions to the remote server (#20049)

TODO:

- [x] Double check strange PHP env detection
- [x] Clippy & etc.

Release Notes:

- Added support for extension languages on the remote server

---------

Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>

crates/proto/src/proto.rs

@@ -368,6 +368,9 @@ messages!(
     (GetPanicFiles, Background),
     (GetPanicFilesResponse, Background),
     (CancelLanguageServerWork, Foreground),
+    (SyncExtensions, Background),
+    (SyncExtensionsResponse, Background),
+    (InstallExtension, Background),
 );
 
 request_messages!(
@@ -491,6 +494,8 @@ request_messages!(
     (GetPathMetadata, GetPathMetadataResponse),
     (GetPanicFiles, GetPanicFilesResponse),
     (CancelLanguageServerWork, Ack),
+    (SyncExtensions, SyncExtensionsResponse),
+    (InstallExtension, Ack),
 );
 
 entity_messages!(