Preliminary implementation of Archive requests. Intermediate commit.

objectstore/CMakeLists.txt

objectstore/cta.proto

scheduler/ArchiveRequest.cpp

scheduler/ArchiveRequest.hpp

scheduler/ArchiveToDirRequest.cpp

scheduler/ArchiveToDirRequest.hpp

scheduler/ArchiveToFileRequest.cpp

scheduler/ArchiveToFileRequest.hpp

scheduler/ArchiveToTapeCopyRequest.cpp

scheduler/ArchiveToTapeCopyRequest.hpp

scheduler/MockSchedulerDatabase.cpp

scheduler/OStoreDB/OStoreDB.cpp

scheduler/OStoreDB/OStoreDB.hpp

scheduler/RetrieveFromTapeCopyRequest.cpp

scheduler/RetrieveFromTapeCopyRequest.hpp

scheduler/RetrieveRequest.cpp

scheduler/RetrieveRequest.hpp

scheduler/RetrieveToDirRequest.cpp

scheduler/RetrieveToDirRequest.hpp

scheduler/RetrieveToFileRequest.cpp