Logging: don't emit ANSI color codes if !isatty()

This CL makes a bunch of changes to logging:
- Move the core logic to a dedicated .cc file
- Add a timestamp in front of the logs (wall time % 1000)
  to better debug across processe (not in the logcat case)s.
- Enables the coloured output only when stderr is a tty.
- Fixes the truncation of the filename to be left-truncated
  rather than right-truncated (which is more useful in general).

Bug: 145150184
Change-Id: Idd7864057ed9411cea0da94ffb7ef520c21bef4f

test/client_api_example.cc

diff --git a/test/client_api_example.cc b/test/client_api_example.cc
index e0f813d..62f04c6 100644
--- a/test/client_api_example.cc
+++ b/test/client_api_example.cc
@@ -16,6 +16,7 @@
 
 #include "perfetto/tracing.h"
 
+#include <chrono>
 #include <thread>
 
 #include "protos/perfetto/config/gpu/gpu_counter_config.pbzero.h"
@@ -100,6 +101,6 @@
       auto* cnt = gpu_packet->add_counters();
       cnt->set_counter_id(1);
     });
-    sleep(1);
+    std::this_thread::sleep_for(std::chrono::seconds(1));
   }
 }