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.metadata.yaml b/xyz/openbmc_project/Common.metadata.yaml
index 36b407c..e1d122a 100644
--- a/xyz/openbmc_project/Common.metadata.yaml
+++ b/xyz/openbmc_project/Common.metadata.yaml
@@ -19,3 +19,5 @@
       type: string
 - name: NoCACertificate
   level: ERR
+- name: TooManyResources
+  level: INFO