Several independent classes were mashed together in mcusupportoptions.cpp
This patch moves McuToolChainPackage together with McuPackage,
McuTarget to its own header+source pair, and
McuKitManager to its own header+source pair.
Task-number: QTCREATORBUG-26890
Change-Id: I0b51da4e1cae5a976201dffd290a665eaa318b33
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>
