Add support for an app in slot 1 and a signature for the same app.
- App digest and app signature is stored in the partition table
- The app is stored in app slot 1
- Two new flags are introduced: -app1 and -app1sig.
- app1: The app binary
- app1sig: A .sig file on a format similar the the files produced by
tkey-sign. Signing algorithm is not checked, it is left to the app
that will validate the signature to specify what algorithm to use.
- sigfile.go is imported from tkey-boot-verifier
Co-authored-by: Mikael Ågren <mikael@tillitis.se>
