Use "lib" in tsconfigs instead of "target". (#13968)

* Use "lib" in tsconfigs instead of "target".

Only add "dom" to libraries that need it. This is determined by a script, so many libraries that have "dom" maybe should not.

* Update new-package and readme

* Add back "target" where necessary

angular-material/tsconfig.json

@@ -5,7 +5,10 @@
     ],
     "compilerOptions": {
         "module": "commonjs",
-        "target": "es6",
+        "lib": [
+            "es6",
+            "dom"
+        ],
         "noImplicitAny": true,
         "noImplicitThis": true,
         "strictNullChecks": false,