Add new ParseRawWithHint() func for X.509-SVID #250
Description
Currently X.509-SVID parsing from raw ASN.1 DER bytes doesn't take into account the SVID hint capability, which requires adding it explicitly to the SVID struct once parsing is complete. Eg here: https://github.com/spiffe/go-spiffe/blob/v2.1.6/v2/workloadapi/client.go#L451-L454.
Maybe having a new function would make things cleaner?
func ParseRawWithHint(certBytes, keyBytes []byte, hint string) (*SVID, error)