Profiler API

Realisation of Profiler agent.
Implemented:
Profiler.enable
Profiler.disable
Profiler.star
Profiler.stop
Profiler.getProfileHeaders
Profiler.getCPUProfile
Profiler.removeProfile
Profiler.clearProfiles
Profiler.addProfileHeader
Profiler.setRecordingProfile
Profiler.resetProfiles

Related: #185
Use a reverse logic to keep the indentation level low:

```js
if (!injected) return;

this._translateEventToFrontend(
  // ...
```