api: vppapitrace JSON/API trace converter

api: vppapitrace JSON/API trace converter

usage: vppapitrace.py [-h] [--debug] [--apidir APIDIR] {convert,replay} ...

optional arguments:
  -h, --help        show this help message and exit
  --debug           enable debug mode
  --apidir APIDIR   Location of JSON API definitions

subcommands:
  valid subcommands

  {convert,replay}  additional help
    convert         Convert API trace to JSON or Python and back
    replay          Replay messages to running VPP instance

To convert an API trace file to JSON:
vppapitrace convert /tmp/api.trace trace.json

To convert an (edited) JSON file back to API trace for replay:
vppapitrace convert trace.json api-edited.trace

To generate a Python file that can be replayed:
vppapitrace convert /tmp/api.trace trace.py
vppapitrace convert trace.json trace.py

Replay it to a running VPP instance:
vppapitrace replay --socket /tmp/api.trace

In VPP that file can be replayed with:
vpp# api trace replay api-edited.trace

This patch also modifies the API binary trace format, to include the
message id to message name table.

Change-Id: Ie6441efb53c1c93c9f778f6ae9c1758bccc8dd87
Type: refactor
Signed-off-by: Ole Troan <ot@cisco.com>