[AppStream] Adding another component type

[Richard Hughes]

Hi,

I've been asked to write some metainfo files for various driver
packages, for instance the nonfree NVIDIA driver. As I want to group
these in the various tools and reports I generate I wanted to create a
new component type rather than just use "generic". Just using generic
would mean I'd have to put logic in multiple places to do things like
icons and sections. I really want to group these together using a
concrete upstream "type" rather than keying off some <metadata> key.

I'm thinking about something like <component type="driver"> but other
ideas welcome. Other ideas that come to mind are "driver-support" or
"hardware-support". Thanks!

Richard