We now support plugins that are more than functions. At the moment these
plugin modules should export a plain object with the following possible
properties:
* priority number
* preload/load priority. Higher numbers result in earlier calling.
* preload function
* Any logic for preloading, just as dynamic/initial setup that may be used by other plugins.
* load
* Any logic for setting up the bulk of the plugin, such as express paths and similar.