ICE/SDP: generate/parse component IDs compliant with RFC-5245

The ICE component IDs are numbered relative to the SDP session, i.e.,
starts from 1 and incremented for each component.
However, RFC-5245 requires that the ICE component IDs are numbered
relative to the media stream, e.g., component IDs 1 and 2 for audio
and component IDs 1 and 2 for video.
This patch allows parsing ICE components IDs in format specified by
the RFC and in the current format.
This patch also allows generating component IDs compliant with
RFC-5245. The generation is disabled by default, and can be enabled
per account on runtime.

Gitlab: #516

Change-Id: I40c0fa54a64b7d729f714c9769ea36335568f4c9