[Cherry Pick] Add consumer API and --query cmdline to list data sources

This CL adds a --query (and --query-raw) cmdline option to
the perfetto cmdline client to list the data sources connected
(whether they are tracing or not) and to retrieve the
DataSourceDescriptor passed at registration time.
--query returns a human readable format (for debugging).
  It does NOT print the full DataSourceDescriptor (because
  it might now know the schema)
  Example: https://pastebin.com/cC9mAWw1
--query-raw is for machine-to-machine and passes through
  the whole tracing_service_state.proto, including the
  DataSourceDescriptor(s).

Cherry-picked from commit 2854a0a9cd1a270c0bf85c9deab91170077362a1

Bug: 132678367
BUG: 140576453
Test: unittests + integrationtests
Merged-In: Id776cc6efe4109ad879380fd6adab8e9d685351a
Change-Id: Id776cc6efe4109ad879380fd6adab8e9d685351a