build: create JS bundles for each component (#6998)

Before this change, all of `@angular/material` was bundled into a
single, flat JS file.

After this change, each top-level component (i.e., each directory under
`src/lib`) will be have its own JS file (and d.ts and metadata.json).

The benefit of this change is that current versions of webpack will be
able to do a much better job of only including the code an app is using.

It also allows (but does not require) people to explicitly import from specific components,
e.g.
```
import {MdButtonModule} from '@angular/material/button';
``

For development _within Angular Material itself_ we have to use these
deeper imports because the root `@angular/material` doesn't exist until
we build the relase package.

Additionally, this PR adds a `tsconfig.json` for each dir under `src/`
with the correct path mappings for that directory, so that IDEs will
correctly generate imports.

Closure Compiler CI check is also disabled by this PR; it cannot work
with the new package structure until a release with
https://github.com/google/closure-compiler/pull/2600 is made available.

scripts/closure-compiler/build-devapp-bundle.sh

@@ -58,9 +58,9 @@ OPTS=(
   "--debug"
 
   # Include the Material and CDK FESM bundles
-  dist/releases/material/@angular/material.js
-  dist/releases/cdk/@angular/cdk.js
-  dist/releases/material-moment-adapter/@angular/material-moment-adapter.js
+  dist/releases/material/esm2015/material.js
+  dist/releases/cdk/esm2015/cdk.js
+  dist/releases/material-moment-adapter/esm2015/material-moment-adapter.js
 
   # Include all Angular FESM bundles.
   node_modules/@angular/core/@angular/core.js
@@ -90,7 +90,7 @@ OPTS=(
 # Walk through every entry-point of the CDK and add it to closure options.
 for i in "${cdkEntryPoints[@]}"; do
   OPTS+=("--js_module_root=dist/releases/cdk/${i}")
-  OPTS+=("dist/releases/cdk/@angular/cdk/${i}.js")
+  OPTS+=("dist/releases/cdk/esm2015/${i}.js")
 done
 
 # Write closure flags to a closure flagfile.