[debugger] TelepathyProcess extracted from DebugMessageView

The main goal of this change is to split logic and UI parts

This is the first step in direction to debugger, which:

1. works with any Telepathy process with DebugInterface support;
2. detects new processess "on fly";
3. has no hardcoded services;
4. shows every single process just once, independently of a number dbus services, registered by the process.

The change also opens a way to QML-based UI

REVIEW: 128847