a more guided installation of sub-plugins

[pfefferle]

@miklb wrote on his wiki page:

I know GWG is working on improvements to the IndieWeb plugin,but right now it's emphasized in the wiki. It just directs people to download 10 more plugins, without doing anything. The ala carte plugins might be great for a seasoned user who wants choices to build IndieWeb into their existing site, but for someone just setting up WP it's overwhelming.

Perhaps we can guide the user a bit more, and explain why to install a plugin or when to skip one. I am using a very simple mechanism to show the plugin "install cards" without using an external class or script, for the OStatus plugin: https://github.com/pfefferle/wordpress-ostatus/blob/master/templates/settings-page.php

Perhaps we can use that to integrate the "install cards" between some more detailed install instructions. An orientation can be the http://indieweb.org/IndieMark