[server] mirate get/set appName from DataQueryOption to ItemsQueryOption

appName is only used in items query.
[server] parse appName query parameter in Itemparameter
[server][RestResourceHost] accept empty "appName"
[server] migrate 'appName' member into ItemsQueryOption from
DataQueryOption
[server][RestresourceHost] avoid variable name crash

'value' is already defined in this scope...
[server][DBTablesMonitoring] remove trailing spaces