Add support for bswap16 and 32. Also rename the existing
`libspdm_le_to_be_64` to `libspdm_byte_swap_64` for consistency.

Signed-off-by: Wilfred Mallawa <[email protected]>

As defined by DSP0826, add support for SPDM storage transport. The
transport layer uses a virtual storage header that encapsulates SPDM
requests to allow the caller to generate the required parameters
for a storage SPDM request. SPDM responses are not transport encoded,
with this header, instead just the message is returned.

Signed-off-by: Wilfred Mallawa <[email protected]>
Signed-off-by: Alistair Francis <[email protected]>

This allows transports such as Storage (DSP0286) to determine if the
next response is protected via secured messages. Unlike other transport
layers, storage does not encode the message type in a response header.
As such, the requester must track the expected type.

The issue [1] discusses this implementation requirement in further
detail with regards to DSP0286.

[1] DMTF/SPDM-WG#3520

Signed-off-by: Wilfred Mallawa <[email protected]>
Signed-off-by: Alistair Francis <[email protected]>

Signed-off-by: Wilfred Mallawa <[email protected]>

Signed-off-by: Wilfred Mallawa <[email protected]>