[cta-admin] Implements streaming "cta-admin drive ls"

cmdline/CMakeLists.txt

cmdline/CtaAdminCmd.cpp

cmdline/CtaAdminTextFormatter.cpp

cmdline/CtaAdminTextFormatter.hpp

xroot_plugins/XrdCtaAdminLs.hpp

xroot_plugins/XrdCtaArchiveRouteLs.hpp

xroot_plugins/XrdCtaDriveLs.hpp

xroot_plugins/XrdCtaTapePoolLs.hpp

xroot_plugins/XrdSsiCtaRequestMessage.cpp

xroot_plugins/XrdSsiCtaRequestMessage.hpp

xrootd-ssi-protobuf-interface