doc(pos-list): add table example

[jg10-mastodon-social]

Candidate to address #134

This adds a storybook example that shows how pos-list can be used to create a table, given that table elements cannot be used, and in absence of a more suited custom component.

I do consider this to require a dashboard creator to be fairly comfortable with HTML and CSS - there's a lot of boilerplate - but I also think it's intuitive enough that someone could copy paste the example and adjust it.

I've added it as a second example in list composition because it's the exact same thing, just styled differently. I'm not sure if that's appropriate.

I've tried to get the aria roles right.

• Tests have been written
  • Example could be affected by future changes to pos-list but this would anyway trigger changes to the storybook. In principle new accessibility tests could be written but this currently relies on browser functionality rather than provided by pos-list
  • N/A. all new code is covered by unit tests
  • N/A. the happy path of a new feature is covered by an end-to-end test
  • manual explorative tests have been performed
• all dependencies are updated to the latest patch version at minimum
• N/A. the CI pipeline passes - no change
• documentation is up-to-date
  • N/A. TSDoc style comments on important functions, properties and events
  • stories for new PodOS elements have been added to storybook
  • N/A. Readme.md files of PodOS elements have been re-generated
  • N/A. architectural decisions are documented as an ADR
  • Changelogs are updated according to
    Keep a Changelog