Function ensure_personal_identity

pub fn ensure_personal_identity<OuterOrigin>(
    o: OuterOrigin,
) -> Result<PersonalId, BadOrigin>
where
    OuterOrigin: TryInto<Origin, Error = OuterOrigin>,

Ensure that the origin o represents an extrinsic (i.e. transaction) from a personal identity. Returns Ok with the personal identity that signed the extrinsic or an Err otherwise.