create x-router/x-route components instead of xcontent

[one-more]

<x-router>
        <x-route pattern="/todo/:id" content="/todo.html"></x-route>
        <x-route pattern="/clock" content="/clock.html"></x-route>
</x-router>

navigation is still through the x-link component

<x-link
   class="nav-link"
   href="/todo"
   text="todo (imba)" >
</x-link>

inside each html could be nesting routers (example for help.html)

<x-router>
        <x-route pattern="/help/faq" content="/faq.html"></x-route>
        <x-route pattern="/help/git" content="/git.html"></x-route>
</x-router>