Pie controls: Introducing a pie delivery service

To make pie controls more reliable, it is neccessary to detect
trigger actions directly from the input stream.
This commit introduces a new system service, that filters all
input events in front of the input dispatcher to detect pie activations.

This commit introduces:
* A new system server local API in the input manager service to register
  secondary input filters. These filters are behind the default
  accessibility filter but before the input event dispatching of
  the android framework.
* A new system service, that binds to the new API to listen for pie
  activation gestures.
* A non-public manager class providing access to the newly created pie
  service.

The service manager name of the service is "pieservice". The non-public
AIDL interface of the service is IPieService.aidl. To register a new
pie activation listener the INJECT_INPUT permission is needed. The
service state can be dumped by the "dumpsys pieservice" command.

Note: This commit only introduces the pie service. There is another
commit, that binds the actual pie controls to the pie service.

Patch Set #1:
* The pie service is currently disabled by default and needs to be
  enabled by device overlays (see config.xml / config_allowPieService).

Patch Set #2:
* Activation fixes
* Debug dump improvements

Patch Set #4:
* Added systrace support (TRACE_INPUT_TAG)
* Switch default to enable service on all devices.
* Moveed Position to com.internal.android.utils.pie.*
* Some more code rearrangements

Change-Id: I6a4a4635bed420e800a3230457ee690131116a11