chore(ngc): refactor out tsc-wrapped

This allows angular's build to depend on some extensions, but not on code generation, and breaks a cycle in the angular build
We now merge ts-metadata-collector into tsc-wrapped and stop publishing the former.

tools/tsc-wrapped/index.ts

@@ -0,0 +1,5 @@
+export {TsickleHost, MetadataWriterHost} from './src/compiler_host';
+export {main, CodegenExtension} from './src/main';
+export {default as AngularCompilerOptions} from './src/options';
+export * from './src/collector';
+export * from './src/schema';