[piotrfila]

Based on talks on discord with @vesim987

This should make some drivers (such as HID) more ergonomic.

Major changes:

• usb.DeviceController options and configuration data are now separate
• usb.DeviceController configuration data now includes driver options
• Some functionality of usb.DeviceController moved to usb.Configuration (which brings us closer to supporting multiple configurations per device)
• Added an example for usb.driver.EchoExample, so that the driver does not bitrot.
• Hopefully made some of the comptime magic more comprehensible [more TODO]
• Added documentation of the usb driver interface [more TODO]
• [TODO] Add check that the comptime driver interface is implemented correctly in drivers