Add signing of the binaries during the build process

[karliatto]

This is a follow up from #14

There was a manually signed binary provided as temporary solution trezor/trezor-suite#6689 but we need this to be as part of the build process so the releases are coming signed at least for the architecture oxs-arm64

[vdovhanych]

Are we the ones who should be signing it, as its being built from the https://github.com/zkSNACKs/WalletWasabi/ ? it will be signed for the suite release eventually and we could resolve the suite issue with singing develop builds using the development certificate.