conference layout implementation

• new button to switch from one layout to another
• display participant info on corresponding tile
• host can select and make one of the participant presenter by right clicking on his/her tile

changed milestone to %Itération 20

added 1 deleted label

added SprintIn progress label

changed milestone to %Itération 21

added SprintDone label and removed SprintIn progress label

assigned to @kkostiuk

mentioned in commit ead4ea11

closed

added typefeature request label