New formula: gnupg-pkcs11

Add new formula gnupg-pkcs11-scd.rb (and formula for dependency pkcs11-helper.rb)

gnupg-pkcs11-scd is GnuPG-compatible smart-card daemon with PKCS#11 support. Depends on pkcs11-helper.

pkcs11-helper is a library that simplifies the interaction with PKCS#11 providers for end-user applications using a simple API and optional OpenSSL engine.