Add ability to invalidate cache entries for Apache

installation/apache-cache-purge.sh.example

@@ -0,0 +1,25 @@
+#!/bin/sh
+
+# A simple shell script to delete a media from Apache's mod_disk_cache.
+
+SCRIPTNAME=${0##*/}
+
+# mod_disk_cache directory
+CACHE_DIRECTORY="/tmp/pleroma-media-cache"
+
+## Removes an item via the htcacheclean utility
+## $1 - the filename, can be a pattern .
+## $2 - the cache directory.
+purge_item() {
+    htcacheclean -p "${2}" "${1}"
+} # purge_item
+
+purge() {
+  for url in "$@"
+  do
+    echo "$SCRIPTNAME delete \`$url\` from cache ($CACHE_DIRECTORY)"
+    purge_item "$url" $CACHE_DIRECTORY
+  done
+}
+
+purge "$@"