Pldmtool change to fetch pdrs based on TerminusID

This commit adds a new option "-n" to getPDR in the pldmtool using
which we can retrieve the PDRs based on the terminus ID.

Tested:
 ./pldmtool platform getpdr -h
get platform descriptor records
Usage: ./pldmtool platform GetPDR [OPTIONS]

Options:
  -h,--help                   Print this help message and exit
  -m,--mctp_eid UINT          MCTP endpoint ID
  -v,--verbose
[Option Group: Required Option]
  Retrieve individual PDR, all PDRs, PDRs of a requested type or retrieve all PDRs of the requested terminusID
  [Exactly 1 of the following options is required]
  Options:
    -d,--data UINT              retrieve individual PDRs from a PDR Repository
                                eg: The recordHandle value for the PDR to be retrieved and 0 means get first PDR in the repository.
    -t,--type TEXT              retrieve all PDRs of the requested type
                                supported types:
                                [terminusLocator, stateSensor, numericEffecter, stateEffecter, EntityAssociation, fruRecord, ... ]
    -i,--terminusID UINT          retrieve all PDRs of the requested terminusID
                                supported IDs:
                                 [1, 2, 208...]
    -a,--all                    retrieve all PDRs from a PDR repository

Example 1:
./pldmtool platform getpdr -i 0
[]

Example 2:
./pldmtool platform getpdr -i 2
Copied the output here:
https://gist.github.com/Pavithrab7/4218104bc7e58951ff91fe5b49e562b0

Change-Id: I8b78818abbbbb3678e180d2bd1f38017454fd0d3
Signed-off-by: Pavithra Barithaya <pavithra.b@ibm.com>
diff --git a/pldmtool/pldm_platform_cmd.hpp b/pldmtool/pldm_platform_cmd.hpp
index 45f15ba..5d548dc 100644
--- a/pldmtool/pldm_platform_cmd.hpp
+++ b/pldmtool/pldm_platform_cmd.hpp
@@ -10,6 +10,13 @@
 
 void registerCommand(CLI::App& app);
 
+/*@brief method to parse the command line option for
+   get PDR command.
+*/
+void parseGetPDROption();
+
+void getPDRs();
+
 } // namespace platform
 
 } // namespace pldmtool