Moved middletier/interface to middletier/common

middletier/CMakeLists.txt

middletier/SQLite/SqliteDatabase.hpp

middletier/SQLite/SqliteMiddleTierAdmin.hpp

middletier/SQLite/SqliteMiddleTierTest.cpp

middletier/SQLite/SqliteMiddleTierUser.hpp

middletier/common/AdminHost.cpp

middletier/common/AdminHost.hpp

middletier/common/AdminUser.cpp

middletier/common/AdminUser.hpp

middletier/common/ArchivalFileTransfer.cpp

middletier/common/ArchivalFileTransfer.hpp

middletier/common/ArchivalJob.cpp

middletier/common/ArchivalJob.hpp

middletier/common/ArchivalJobQueues.cpp

middletier/common/ArchivalJobQueues.hpp

middletier/common/ArchivalJobState.cpp

middletier/common/ArchivalJobState.hpp

middletier/common/ArchivalMount.cpp

middletier/common/ArchivalMount.hpp

middletier/common/ArchivalRequest.cpp