Update lit-starter-ts to lit-next

* Upgrades the source to work with lit-next
* Aligns the linting and formatting rules/settings & ignores with the monorepo
* Upgrades to the same version of typescript and tsconfig settings as the monorepo
* Upgrades the test runner from karma to web-test-runner
* Upgrades the dev server from es-dev-server to @web/dev-server

rollup.config.js

@@ -12,9 +12,9 @@
  * http://polymer.github.io/PATENTS.txt
  */
 
-import filesize from 'rollup-plugin-filesize';
+import summary from 'rollup-plugin-summary';
 import {terser} from 'rollup-plugin-terser';
-import resolve from 'rollup-plugin-node-resolve';
+import resolve from '@rollup/plugin-node-resolve';
 import replace from '@rollup/plugin-replace';
 
 export default {
@@ -32,6 +32,7 @@ export default {
     replace({'Reflect.decorate': 'undefined'}),
     resolve(),
     terser({
+      ecma: 2017,
       module: true,
       warnings: true,
       mangle: {
@@ -40,8 +41,6 @@ export default {
         },
       },
     }),
-    filesize({
-      showBrotliSize: true,
-    }),
+    summary(),
   ],
 };