refactor(compiler): bump metadata version to 4 (#19338)

Also adds auto upgrade from lower version based
on the .d.ts file (e.g. from version 3 to 4).

This is needed as we are now also capturing type aliases
in metadata files (and we rely on this),
see 6e3498ca8e.

packages/compiler-cli/index.ts

@@ -15,6 +15,7 @@ export {getClassMembersFromDeclaration, getPipesTable, getSymbolQuery} from './s
 export {Extractor} from './src/extractor';
 export {VERSION} from './src/version';
 
+export * from './src/metadata';
 export * from './src/transformers/api';
 export * from './src/transformers/entry_points';