Install node application dependencies into the common unprivileged
directory defined and managed by RunsConfig, and define NODE_PATH
such that node applications will search the directory for modules.
This fixes the optimization of image layers by using the original
location for installed modules instead of performing a subsequent move
of the modules back into the project directory. The latter may or may
not result in an additional fs layer depending on the backing storage,
making the previous install/move method unreliable.