Display taxonomies in sidebar

[chunned]

Fixes #79

Displays taxonomies in sidebar like:

            <p>
            categories: 
                <a href="[/categories/homelab](view-source:http://localhost:1313/categories/homelab)">homelab</a>
            </p>
            <p>
            tags: 
                <a href="[/tags/cybersecurity](view-source:http://localhost:1313/tags/cybersecurity)">cybersecurity</a>, 
                <a href="[/tags/hacking](view-source:http://localhost:1313/tags/hacking)">hacking</a>
            </p>

edit: Meant to merge this into my fork, not here, since there is already another PR open.