THE USE OF VISION AND VOICE TRANSMITTING VIDEO CONFERENCE SYSTEM IN CRIMINAL PROCEEDINGS (VIDEO CONFERENCE METHOD IN THE HEARINGS) AND ITS FEASIBILITY DURING THE COVID 19 PANDEMIC AND THE APPROACH OF EUROPEAN COURT OF HUMAN RIGHTS (ECHR) TOWARDS THE VISION AND VOICE TRANSMITTING VIDEO CONFERENCE SYSTEM (THE VIDEO CONFERENCE METHOD): THE CRITERIAS SET BY THE PRECEDENT JUDGMENT GIVEN IN THE ACTION OF MARCELLO VIOLA/ITALY IN THE CONTEXT OF FAIR TRIAL