Function add_secret 

pub fn add_secret(
    vault: &mut Vault,
    murk: &mut Murk,
    key: &str,
    value: &str,
    desc: Option<&str>,
    scoped: bool,
    tags: &[String],
    identity: &Identity,
) -> bool

Add or update a secret in the working state. If scoped is true, stores in scoped (encrypted to self only). Returns true if the key was new (no existing schema entry).