refactor(types): widen Component type to include consutructor types

returned from `defineComponent`

ref: https://github.com/vuejs/vue-router-next/pull/421
also close #1880

Previous `Component` type is now exported as `ConcreteComponent`.

This introduces a minor breaking change when calling `h(comp, { ... })`
will now fail if `comp` is a of generic `Component` type, since it does
not specify what props it expects.

packages/runtime-core/src/index.ts

@@ -159,6 +159,7 @@ export {
 } from './vnode'
 export {
   Component,
+  ConcreteComponent,
   FunctionalComponent,
   ComponentInternalInstance,
   SetupContext,
@@ -178,7 +179,7 @@ export {
 export {
   ComponentPublicInstance,
   ComponentCustomProperties
-} from './componentProxy'
+} from './componentPublicInstance'
 export {
   Renderer,
   RendererNode,