dev: make devcontainer setup plugin agnostic

.devcontainer/20_init_plugin

@@ -0,0 +1,24 @@
+#!/bin/bash
+set -eo pipefail
+
+log-info() {
+  declare desc="Log info formatter"
+  echo "    $*" 1>&2
+}
+
+log-fail() {
+  declare desc="Log fail formatter"
+  echo "!   $*" 1>&2
+  exit 1
+}
+
+main() {
+  dokku plugin:install
+
+  # built in the Dockerfile
+  PLUGIN_NAME="$(source /tmp/.env && echo "$PLUGIN_NAME")"
+  PLUGIN_VARIABLE="$(source /tmp/.env && echo "$PLUGIN_VARIABLE")"
+  dokku config:set --global "${PLUGIN_VARIABLE}_HOST_ROOT=${SERVICE_HOST_ROOT}"
+}
+
+main "$@"