tester: split simple call tests in two suites: video calls and other calls and minor files reorganization

Also, the RTP sockets are now always IPv6 when ipv6 is enabled in LinphoneCore,
independently of what is finally proposed in SDP, so that these sockets can always send and recv
with both versions.
This is consistent with what is already done in belle-sip for SIP sockets.

keep using periodical updates (even for non-existent streams) at least for tests, because it is convenient to be notified everytime linphonecore updates
bandwidth measurement.
This may change in the future when bandwidth computations will be done in real time (every mediastreamer2 tick).

fix crash in linphone_core_destroy() when releasing the chat rooms while belle_sip_provider_t no longer exists, and fix many memory leaks

chat: refactoring it to always invoke callbacks when changing state, reenable disabled tests and add two new file upload tests where liblinphone should not crash while it does currently

fix bugs in Paused state management. It was possible to transition from Paused to PausedByRemote, which actually breaks the Paused state, and eventually allows the pauser to be resumed by the paused.

Instead of just relying on bandwidth measurement, use video frame decoded callback.
Some bandwidth assumption look inconsistent with what the test is doing, they have been modified.

repair liblinphone_tester (android) and enable call with file player and rtp io test to run ms_audio_diff on embedded platforms, since it is much faster
than originally.