Trim container a little bit. #126

Job	Run time
runtime-container-job	1m 1s
builder-container-job	5m 50s
spacktainer-build-job (appositionizer)	3m 12s
spacktainer-build-job (brain-indexer)	5m 6s
spacktainer-build-job (brayns)	8m 56s
spacktainer-build-job (connectome-manipulator)	9m 15s
spacktainer-build-job (functionalizer)	13m 35s
spacktainer-build-job (multiscale-run)	40m 24s
spacktainer-build-job (neurodamus-hippocampus)	5m 28s
spacktainer-build-job (neurodamus-neocortex)	4m 30s
spacktainer-build-job (system-benchmarks)	2m 19s
	1h 39m 36s

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