clarify scope of different "policies and practices"

[tmchartrand]

My understanding is that some of these pages truly apply to all of AIND (data organization/governance) while some are more narrowly targeted (software and docs practices), reflecting standards we apply to scicomp, SIPE, and production pipelines.
I think we need to be really clear about this! and try to make the docs organization reflect this also.

[dbirman]

• Clarify in the headers that this is for maintained production packages https://docs.allenneuraldynamics.org/en/latest/policies_practices/software_practices.html