Consider using UUID to identify platforms and applets

[ia0]

We could use UUID v8 to identify platforms (currently called "serial") and applets (currently called "stable identifier" in the book).

xxxxxxxx-yyyy-zzzz-zzzz-yyyyxxxxxxxx
              8a5e b140              = identifies a platform
              8a5e ab17              = identifies an applet
         ~~~~           ~~~~         ~ identifies a vendor (32 bits)
         8a5e-8a5e-b140-b057         = host runner (configurable device id)
         8a5e-8a5e-b140-5284         = nordic runner (FICR device id)
         8a5e-8a5e-ab17-ab17         = example applets (8 bytes name)
~~~~~~~~                    ~~~~~~~~ ~ identifies a device/applet (64 bits)
00000000-8a5e-8a5e-b140-b05700000000 = default host runner
600cce02-8a5e-8a5e-b140-5284b25b6ef2 = example nordic runner
68656c6c-8a5e-8a5e-ab17-ab176f000000 = hello example applet