Update to Hugo 0.53 and remove all .Site references (#12079)

* Remove all .Site variable references

* Update Hugo version in Travis CI config and Makefile

layouts/shortcodes/blocks/__common.html

@@ -1,7 +1,7 @@
 {{/* This file contains some common template definitions used in the blocks shortcodes. 
 The reasoning behind the long and hard-to-remember template names is that these templates are global. */}}
 {{ define "shortcodes-blocks_getimage" }}
-{{- $cr := .ctx.Site.GetPage "/_common-resources" -}}
+{{- $cr := site.GetPage "/_common-resources" -}}
 {{- with $cr -}}
 {{- $image := $cr.Resources.GetMatch (printf "images/**%s*" $.name ) -}}
 {{- with $image -}}
@@ -12,4 +12,4 @@ The reasoning behind the long and hard-to-remember template names is that these
 {{- else -}}
 {{ errorf "[%s] No resource bundle found. Create an empty headless bundle; create content/%s/_common-resources/index.md with \"headless: true\" in front matter. See https://gohugo.io/content-management/page-bundles/#headless-bundle"  $.ctx.Page.Lang $.ctx.Page.Lang }}
 {{- end -}}
-{{- end -}}
+{{- end -}}