Add function to decrypt using sops

Would like to have a sops function to decrypt a file using the sops tool. So then I could write something like {{- Files.Get "keystore.p12.enc" | decrypt | b64enc | nindent 4 }}.

Not sure of all the options that can be passed to sops to decrypt and which ones need to be available in the sprig library.

+1. Even if not sops, just general execution of command, like exec/sh/etc.