feat: add storage directory mode and removal flags

`storage:create` and `storage:set` accept a `--mode` flag that sets the octal permissions of a docker-local host directory, and `storage:destroy` accepts a `--destroy-host-dir` flag that removes the directory along with its contents. A docker-local entry also honors `--reclaim-policy Delete` at destroy time now, matching how that policy governs a k3s PersistentVolume. Both are limited to the default `/var/lib/dokku/data/storage/<name>` location, the same restriction `--chown` already carries. `storage:set` applies `--chown` and `--mode` to the directory rather than only recording them.

plugins/storage/bin/chmod-storage-dir

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+set -eo pipefail
+[[ $DOKKU_TRACE ]] && set -x
+
+main() {
+  declare desc="chmods a storage directory"
+  declare DIRECTORY="$1" MODE="$2"
+
+  if [[ -z "$DIRECTORY" ]]; then
+    echo " !     Please specify a directory to chmod" 1>&2
+    exit 1
+  fi
+
+  if [[ ! "$DIRECTORY" =~ ^[A-Za-z0-9\\_-]+$ ]]; then
+    echo " !     Directory can only contain the following set of characters: [A-Za-z0-9_-]" 1>&2
+    exit 1
+  fi
+
+  if [[ ! "$MODE" =~ ^[0-7]{3,4}$ ]]; then
+    echo " !     Unsupported directory mode. Value must be a 3 or 4 digit octal mode, such as 0755" 1>&2
+    exit 1
+  fi
+
+  chmod "$MODE" "${DOKKU_LIB_ROOT}/data/storage/$DIRECTORY"
+}
+
+main "$@"

plugins/storage/bin/destroy-storage-dir

@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+set -eo pipefail
+[[ $DOKKU_TRACE ]] && set -x
+
+main() {
+  declare desc="removes a storage directory and its contents"
+  declare DIRECTORY="$1"
+
+  if [[ -z "$DIRECTORY" ]]; then
+    echo " !     Please specify a directory to destroy" 1>&2
+    exit 1
+  fi
+
+  if [[ ! "$DIRECTORY" =~ ^[A-Za-z0-9\\_-]+$ ]]; then
+    echo " !     Directory can only contain the following set of characters: [A-Za-z0-9_-]" 1>&2
+    exit 1
+  fi
+
+  local storage_path="${DOKKU_LIB_ROOT}/data/storage/$DIRECTORY"
+
+  if [[ ! -e "$storage_path" ]]; then
+    exit 0
+  fi
+
+  if [[ ! -d "$storage_path" ]]; then
+    echo " !     $storage_path exists but is not a directory" 1>&2
+    exit 1
+  fi
+
+  rm -rf "$storage_path"
+}
+
+main "$@"