Add gdb to Neurodamus containers #136

Job	Run time
builder-container-job	6m 19s
runtime-container-job	1m 13s
spacktainer-build-job (appositionizer)	14m 43s
spacktainer-build-job (brain-indexer)	40m 34s
spacktainer-build-job (connectome-manipulator)	1h 11m 31s
spacktainer-build-job (functionalizer)	1h 9m 52s
spacktainer-build-job (neurodamus-hippocampus)	46m 9s
spacktainer-build-job (neurodamus-neocortex)	44m 29s
spacktainer-build-job (neurodamus-thalamus)	44m 13s
spacktainer-build-job (system-benchmarks)	21m 2s
	6h 0m 5s

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