Add PLDM.Requester interface

This interface has APIs that help PLDM requester apps on the BMC to
construct PLDM request messages.

Also introduce the exception
xyz.openbmc_project.Common.Error.TooManyResources, which is analogous to
the errno ENFILES.

Signed-off-by: Deepak Kodihalli <dkodihal@in.ibm.com>
Change-Id: I79632bccb002d5afabd4381ae27a0b7ac6476aa7
diff --git a/xyz/openbmc_project/Common.errors.yaml b/xyz/openbmc_project/Common.errors.yaml
index e5d8421..90b0e91 100644
--- a/xyz/openbmc_project/Common.errors.yaml
+++ b/xyz/openbmc_project/Common.errors.yaml
@@ -10,3 +10,5 @@
   description: The operation is not allowed
 - name: NoCACertificate
   description: Server's CA certificate has not been provided.
+- name: TooManyResources
+  description: Too many resources have already been granted.