Plugin weights UI, part II

The plugin weights configuration has been a source of confusion for too long.
See #1404018: Better UI for hierarchical prioritization form
In the 7.x-2.x branch the textual widget has been replaced by a tabledrag form. But from the feedback I get (not too much, actually, but almost anyone I introduce to the module), it is still confusing.

I am suggesting a new UI, where the configuration happens on a number of separate pages, instead of being squeezed all on one page.

• admin/structure/crumbs/weights
  This will be the tabledrag form, but only the top section with the "enabled" plugin keys.
  It is used to prioritize those keys, but will NOT allow to change the status (enabled, disabled, inherit).
  Below it, there will be a list of the explicitly disabled plugin keys, but this list will NOT be interactive.
• admin/structure/crumbs/plugin-keys/%crumbs_plugin_key
  This will contain a form to set the status (enabled, disabled, inherit) of a specific plugin key, using a radio elements.

The new form will contain

• A longer description of, and information about the plugin key.
• Links to the parent plugin keys.
• The radio options, with a detailed explanation for each option.
• Links to the child plugin keys.

The attached image has a preview of the new form.
The description should be more detailed, and contain information about the plugin type (parent-finding or title-finding) and which routes it applies to.

The intro text and the option labels / descriptions will be different for the root plugin key ("*"), and for plugins that are "disabled by default".