PSA_KEY_DERIVATION_INPUT_PASSWORD macro

A low-entropy secret input for password hashing / key stretching. This is usually a key of type #PSA_KEY_TYPE_PASSWORD (passed to psa_key_derivation_input_key()) or a direct input (passed to psa_key_derivation_input_bytes()) that is a password or passphrase. It can also be high-entropy secret such as a key of type #PSA_KEY_TYPE_DERIVE or the shared secret resulting from a key agreement. The secret can also be a direct input (passed to key_derivation_input_bytes()). In this case, the derivation operation may not be used to derive keys: the operation will only allow psa_key_derivation_output_bytes(), psa_key_derivation_verify_bytes(), or psa_key_derivation_verify_key(), but not psa_key_derivation_output_key().