soa container import

• this makes SOAContainer available as INCLUDE_DIRS Kernel/SOAContainer and #include "SOAContainer/SOAView.h".

• this won't work with git lb-checkout (no submodule support). We assume this won't be much of a problem anyway as the SOAContainer will probably result in binary incompatible code when updated, so one would effectively need to rebuild LHCb if one tries to modify the deployed SOAContainers. (We're trying to convince ourselves that we don't need to have a bad conscience for putting won't-fix on this one)

• nightlies should be fine, Marco checks out submodules as well (although we didn't use them outside lbscripts(?))

• the recursive checkout will require access to github.com