[Canvas] rename config parameter "appsInitialization" -> "appsInit"
[Canvas] move duplicate parts into method
[Canvas] more semantic method names; get rid of duality of app destruction
[Canvas] rename config parameter "appInitializationTimeout" -> "appInitTimeout"
[Canvas] move grid building to the renderer
[Canvas] add comment + remove unnecessary if-statement
[Canvas, tests] update Canvas config due to renaming the config parameter