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

docs-src/install.md

@@ -20,11 +20,13 @@ npm CDNs like [unpkg.com]() can directly serve files that have been published to
 For this element to work from unpkg.com specifically, you need to include the `?module` query parameter, which tells unpkg.com to rewrite "bare" module specificers to full URLs.
 
 ### HTML
+
 ```html
 <script type="module" src="https://unpkg.com/my-element?module"></script>
 ```
 
 ### JavaScript
+
 ```html
 import {MyElement} from 'https://unpkg.com/my-element?module';
 ```