[Enhancement] Routing concept with cookbook example

Describe the enhancement

Add tab routing concept with router-outlet to tab-navigation and amend cookbook with an example. A POC on the feasibility of using Angular's native routing has been conducted with participation of @RasmusTraeholt and @mark-drastrup. The use of Angular's native relative-routing and named-outlets a.k.a. auxiliary-routing was tested on the cookbook example but proved not to work as intended. A working solution was chosen based on absolute routing where the absolute route to the navigation tab was provided using a router attribute. It is to be decided whether the absolute path of the nav-tab router-link should be specified using Angular's routerLink attribute or specified using a custom attribute on the tab-nav component(s).

Describe the solution you'd like

[ ] Add route parameter to the tab-nav-item and router-outlet to the tab-nav component(s).
[ ] Revise the cookbook page tab-nav example to use the router concept.

Have you considered any alternatives?

Are there any additional context?

Checklist:

The following tasks should be carried out in sequence in order to follow the process of contributing correctly.

Refinement

[ ] Request that the issue is UX refined; do not proceed until this is done.
[ ] Request that the issue is tech refined; do not proceed until this is done.

Implementation

The contributor who wants to implement this issue should:

[ ] Make sure you have read: "Before you get coding".
[ ] Signal to others you are working on the issue by assigning yourself.
[ ] Create a branch from the develop branch following our branch naming convention.
[ ] Publish a WIP implementation to Github as a draft PR and ask for feedback.
[ ] Make sure you have implemented tests following the guidelines in: "The good: Test".
[ ] Update the cookbook with examples and showcases.

Review

Once the issue has been implemented and is ready for review:

[ ] Do a self-review.
[ ] Create a pull-request. If you created a draft PR during implementation you can just mark that as "ready for review".

kirbydesign / designsystem