initrc file for Perfetto

This CL turns the perfetto daemons into two standalone
executable. Given the amount of shared code between the
two (traced and traced_probes) the code is shared in a
.so library.
Also adds the corresponding initrc files.

Corresponding /sepolicy/ changes:
https://android-review.googlesource.com/c/platform/system/sepolicy/+/574422

Change-Id: I3566d31757dd7fbf2478ca6512a6b655753a7fd6
diff --git a/Android.bp b/Android.bp
index 4e32744..47d8b10 100644
--- a/Android.bp
+++ b/Android.bp
@@ -900,6 +900,9 @@
     "libtraced_shared",
     "libutils",
   ],
+  init_rc: [
+    "perfetto.rc",
+  ],
   defaults: [
     "perfetto_defaults",
   ],