feat: add json output format support to storage:list

This will allow the command to be used in a programmatic fashion.

plugins/storage/functions

@@ -26,6 +26,6 @@ get_bind_mounts() {
   declare desc="strips docker options and prints mounts"
   local -r phase_file_path=$1
   if [[ -r "$phase_file_path" ]]; then
-    sed -e '/^-v/!d' -e 's/^-v/    /' <"$phase_file_path"
+    sed -e '/^-v/!d' -e 's/^-v //' <"$phase_file_path"
   fi
 }