`js-example-app` ssr improvements

[faselbaum]

Description / User story

This is a collection of improvements we should consider for the js-example-app

• [ ] A) Offer a "production" build that inlines / bundles all JS dependencies so that the page becomes interactive immediately after first paint. Solves https://github.com/deven-org/boiler/pull/1103#discussion_r1636091151
• [ ] B) Investigate and fix server side rendering and hydration of the following components: Select | TabBar. They are currently missing slotted elements.
• [ ] C) Investigate potential performance gains by abandoning stream rendering in favour of string rendering.