<runtime> Card origin_runtime_213: realtime node_utilization checks

Add fact and resource_limits.conf entry for no_overcommit_active

Add flock around container creation and additional check for node
capacity if no_overcommit_active is true, add GearCreationException
for this case, and add return code of 146 to oo-app-create if it
gets GearCreationException on create

Better error to user when gear creation is aborted for exceeding
max_active_gears when no_overcommit_active is true

cache resource_limits.conf in node model

added unit test for no_overcommit_active

added unit test for node_utilization
Fix up unit test to prevent test pollution, fix variable name typo