Make the external opener a two phase process

This changes makes a few changes to the openers:

- Move the opener prompting from the extension host into the main thread
- Make the external opener process two phases: get openers and then open. This would let us skip the trusted domain validation for extension handled links if we want to in the future
- Add lifecycle to commands used by the uri opener

For #109277

src/vs/workbench/api/common/extHost.protocol.ts

@@ -806,7 +806,9 @@ export interface MainThreadUriOpenersShape extends IDisposable {
 }
 
 export interface ExtHostUriOpenersShape {
-	$openUri(uri: UriComponents, ctx: { originalUri: UriComponents }, token: CancellationToken): Promise<boolean>;
+	$getOpenersForUri(uri: UriComponents, token: CancellationToken): Promise<{ cacheId: number, openers: ReadonlyArray<{ id: number, title: string }> }>;
+	$openUri(id: ChainedCacheId, uri: UriComponents): Promise<void>;
+	$releaseOpener(cacheId: number): void;
 }
 
 export interface ITextSearchComplete {