Doc: merge https://github.com/mguessan/davmail/pull/461
O365: revert default redirectUri to https://login.microsoftonline.com/common/oauth2/nativeclient, live.com authentication expects this default value, users can still override with localhost in manual authentication mode
Graph: switch back to id as main itemName on calendar events
Caldav: detect and ignore Thunderbird fake put request
Graph: review getEventIfExists and implement sendEvent (outbox)
Graph: exclude default calendar in getSubCalendarFolders
Caldav: XML encode displayname on subfolders, only warn on missing items
Graph: add isDefaultCalendar property to calendar folders, specific implementation for getSubCalendarFolders