message.proto: do not export mkwrapper messages to nanopb/RT
message.proto: do not export mkwrapper messages to nanopb/RT

the [(nanopb).type = FT_IGNORE] option tells the nanopb generator to
ignore this field, meaning no descriptor references are added to the
generated C code.

This is good practice for messages which are never used in RT. Otherwise,
the corresponding .c file needs to linked into the pbmsgs module
(see src/machinetalk/msgcomponents/Submakefile) and the corresponding
extern reference exported in pbmsgs.c .

This also removes "missing symbol" messages during a kthreads build.

araisrobo/QtQuickVcp,qtquickvcp/QtQuickVcp,araisrobo/QtQuickVcp,bobvanderlinden/machinetalk-protobuf,araisrobo/QtQuickVcp,machinekit/machinetalk-protobuf,machinekoder/QtQuickVcp,bobvanderlinden/QtQuickVcp,strahlex/machinetalk-protobuf,mhaberler/machinetalk-protobuf,JDSquared/QtQuickVcp,qtquickvcp/QtQuickVcp,mhaberler/machinetalk-protobuf,bobvanderlinden/QtQuickVcp,strahlex/machinetalk-protobuf,bobvanderlinden/machinetalk-protobuf-node,JDSquared/QtQuickVcp,qtquickvcp/QtQuickVcp,JDSquared/QtQuickVcp,machinekit/machinetalk-protobuf,machinekit/machinetalk-protobuf,strahlex/QtQuickVcp,mhaberler/machinetalk-protobuf,bobvanderlinden/machinetalk-protobuf-node,qtquickvcp/QtQuickVcp,strahlex/QtQuickVcp,bobvanderlinden/QtQuickVcp,machinekoder/QtQuickVcp,mhaberler/machinetalk-protobuf,bobvanderlinden/machinetalk-protobuf,bobvanderlinden/machinetalk-protobuf-node,araisrobo/QtQuickVcp,machinekoder/QtQuickVcp,machinekoder/QtQuickVcp,machinekit/machinetalk-protobuf,JDSquared/QtQuickVcp,strahlex/QtQuickVcp