Add standard Luigi Container examples

[ndricimrr]

We have plenty of starter examples for Luigi Core based apps but we don't have any standard one for Luigi Container usage.

Current linked example for Luigi Container was mostly built for testing reasons and not as a Getting Started Example.
Check ./test-app/index.html for how it is used. --> index.html is very huge and complicated, this can be used for internal testing but is not suitable as a showcase simple example.

• Add examples suitable for Luigi Container and Luigi Compound Container to give people an easy start into it.

• Container README also needs to be changed accordingly

• Since the README is used when releasing, need to also issue a new Container release, just so that the npm package description has the proper instructions for Getting Started examples.

• These examples should also show up in the Luigi Docu Website, Just like https://docs.luigi-project.io/docs/getting-started but at a respective other route. Figure out how we add new items to the Docu and how and where to put it.

Possible Solution:

• Two simple example of using LuigiContainer
  • 1 using Iframe based microfrontend
  • 1 using web-component based microfrontend
• 1 simple example of using LuigiCompoundContainer

One idea of how to organise the file structure could be:

• container/examples/container-iframe
  • index.html
  • package.json
  • microfrontend.html
  • README.md
• container/examples/container-wc
  • index.html
  • package.json
  • myWebComponent.js
  • README.md
• container/examples/compound-container
  • index.html
  • package.json
  • myCompoundWebComponent.js
  • myCompoundWebComponent2.js
  • (... any needed file for a simple compound container configuration. )
  • README.md

For now, do not overcomplicate things, a super simple HTML file should be enough. package.json can be used just to run a small local server for serving the index.html file, skipping unnecessary imported libraries to avoid extra future maintenance.