spdm: Add requester library

Add the requester library that will be used by CrOS userland in the
future. Note that unlike the responder library, this doesn't need to be
build in embedded and doesn't need to put too much effort on saving code
size.

Implement the basic GetVersion functionality.

BUG=b:335386464
TEST=spdm unittests

Change-Id: I64d7f391ee5a32229d85771242a62b43e5869eae
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/spdm/+/5461175
Tested-by: Howard Yang <hcyang@google.com>
Reviewed-by: Vadim Sukhomlinov <sukhomlinov@google.com>
Commit-Queue: Howard Yang <hcyang@google.com>
12 files changed