jamiaccount: add manager configuration property

MSVC/ring-daemon.vcxproj

MSVC/ring-daemon.vcxproj.filters

src/dring/account_const.h

src/jamidht/Makefile.am

src/jamidht/account_manager.cpp

src/jamidht/account_manager.h

src/jamidht/archive_account_manager.cpp

src/jamidht/archive_account_manager.h

src/jamidht/contact_list.cpp

src/jamidht/contact_list.h

src/jamidht/jamiaccount.cpp

src/jamidht/jamiaccount.h

src/jamidht/namedirectory.h

src/jamidht/server_account_manager.cpp

src/jamidht/server_account_manager.h