feat: introduce source maps for templates (#15011)

The main use case for the generated source maps is to give
errors a meaningful context in terms of the original source
that the user wrote.

Related changes that are included in this commit:

* renamed virtual folders used for jit:
  * ng://<module type>/module.ngfactory.js
  * ng://<module type>/<comp type>.ngfactory.js
  * ng://<module type>/<comp type>.html (for inline templates)
* error logging:
  * all errors that happen in templates are logged
    from the place of the nearest element.
  * instead of logging error messages and stacks separately,
    we log the actual error. This is needed so that browsers apply
    source maps to the stack correctly.
  * error type and error is logged as one log entry.

Note that long-stack-trace zone has a bug that 
disables source maps for stack traces,
see https://github.com/angular/zone.js/issues/661.

BREAKING CHANGE:

- DebugNode.source no more returns the source location of a node.  

Closes 14013

tools/public_api_guard/core/typings/core.d.ts

@@ -302,7 +302,7 @@ export declare class DebugElement extends DebugNode {
     styles: {
         [key: string]: string;
     };
-    constructor(nativeNode: any, parent: any, _debugInfo: RenderDebugInfo);
+    constructor(nativeNode: any, parent: any, _debugContext: DebugContext);
     addChild(child: DebugNode): void;
     insertBefore(refChild: DebugNode, newChild: DebugNode): void;
     insertChildrenAfter(child: DebugNode, newChildren: DebugNode[]): void;
@@ -325,8 +325,8 @@ export declare class DebugNode {
     readonly references: {
         [key: string]: any;
     };
-    readonly source: string;
-    constructor(nativeNode: any, parent: DebugNode, _debugInfo: RenderDebugInfo);
+    /** @deprecated */ readonly source: string;
+    constructor(nativeNode: any, parent: DebugNode, _debugContext: DebugContext);
 }
 
 /** @deprecated */