LibCrypto: PK encrypt/decrypt/sign/verify methods do not return errors

[ADKaster]

Instead these methods return void, and the implementations log their errors to dbgln. This makes it hard for callers to react to errors and report them properly. Currently thinking of Web Crypto as one user.

This is probably an issue throughout LibCrypto/LibTLS as well? I believe the DER decoder methods have the same issue.