extension: Update DAP extension API (#32448)

- DAP schemas will be stored in `debug_adapters_schemas` subdirectory in
extension work dir.
- Added Debug Config integration and such.

Release Notes:

- N/A

crates/dap_adapters/src/php.rs

@@ -110,7 +110,7 @@ impl PhpDebugAdapter {
 
 #[async_trait(?Send)]
 impl DebugAdapter for PhpDebugAdapter {
-    async fn dap_schema(&self) -> serde_json::Value {
+    fn dap_schema(&self) -> serde_json::Value {
         json!({
             "properties": {
                 "request": {