Move cluster-capabilities-table to a headless bundle and include it as a page instead of reading the file

This prevents the table to automatically be included on pages of other bundles.
By including the page instead of reading the file also the shortcodes in the table are expanded correctly.

This fixes broken links in the table.

Fixes https://github.com/rancher/docs/issues/2577

Signed-off-by: Bastian Hofmann <bashofmann@gmail.com>

layouts/shortcodes/include.html

@@ -0,0 +1,5 @@
+{{$file := .Get "file"}}
+
+{{- with .Site.GetPage $file -}}
+{{- .Content | markdownify -}}
+{{- end -}}