fix: remove relURL from markdown render image hook (#93)

* fix: remove relURL from markdown render image hook

BREAKING CHANGE: As the relURL function in markdown render hooks
caused some unwanted side effects we had to remove it. Related to this
change the behavior for sites deployed to a subdirectory has changed as
well! Please check the [documentation](https://geekdocs.de/usage/getting-started/#sub-directories)
how to workaround subdirectory deployments.

* restructure color-schemes page to work as image bundle example

* fix wording

layouts/partials/head.html

@@ -31,4 +31,8 @@
     {{ printf `<link rel="%s" type="%s" href="%s" title="%s" />` .Rel .MediaType.Type .Permalink $.Site.Title | safeHTML }}
 {{ end -}}
 
+{{ if (default false $.Site.Params.GeekdocOverwriteHTMLBase) }}
+<base href="{{ .Site.BaseURL }}">
+{{ end }}
+
 {{ printf "<!-- %s -->" "Made with Geekdoc theme https://github.com/thegeeklab/hugo-geekdoc" | safeHTML }}