feat: add a Railpack builder to Dokku

Closes #7615

plugins/builder-railpack/subcommands/default

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+source "$PLUGIN_AVAILABLE_PATH/builder-railpack/help-functions"
+set -eo pipefail
+[[ $DOKKU_TRACE ]] && set -x
+
+cmd-builder-railpack-help "builder-railpack:help"

plugins/builder-railpack/subcommands/report

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+source "$PLUGIN_AVAILABLE_PATH/builder-railpack/internal-functions"
+set -eo pipefail
+[[ $DOKKU_TRACE ]] && set -x
+
+cmd-builder-railpack-report "$@"

plugins/builder-railpack/subcommands/set

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
+source "$PLUGIN_CORE_AVAILABLE_PATH/common/property-functions"
+set -eo pipefail
+[[ $DOKKU_TRACE ]] && set -x
+
+cmd-builder-railpack-set() {
+  declare desc="set or clear a builder-railpack property for an app"
+  declare cmd="builder-railpack:set"
+  [[ "$1" == "$cmd" ]] && shift 1
+  declare APP="$1" KEY="$2" VALUE="$3"
+  local VALID_KEYS=("railpackjson-path" "no-cache")
+  [[ "$APP" == "--global" ]] || verify_app_name "$APP"
+
+  [[ -z "$KEY" ]] && dokku_log_fail "No key specified"
+
+  if ! fn-in-array "$KEY" "${VALID_KEYS[@]}"; then
+    dokku_log_fail "Invalid key specified, valid keys include: railpackjson-path, no-cache"
+  fi
+
+  if [[ -n "$VALUE" ]]; then
+    dokku_log_info2_quiet "Setting ${KEY} to ${VALUE}"
+    fn-plugin-property-write "builder-railpack" "$APP" "$KEY" "$VALUE"
+  else
+    dokku_log_info2_quiet "Unsetting ${KEY}"
+    fn-plugin-property-delete "builder-railpack" "$APP" "$KEY"
+  fi
+}
+
+cmd-builder-railpack-set "$@"