Add documentation standards

[dougollerenshaw]

Add documentation standards directory

This PR creates a new documentation_standards directory containing:

1. README.md - Overview of AIND documentation requirements and repository categories
2. data_acquisition_doc_standard.md - Documentation standard for data acquisition repositories
3. code_ocean_capsule_doc_standard.md - Documentation standard for Code Ocean capsules
4. code_ocean_pipeline_doc_standard.md - Documentation standard for Code Ocean pipelines

These standards define minimum documentation requirements for different types of AIND repositories, ensuring consistency across the organization and avoiding the continued propagation of repositories/capsules/pipelines without any documentation.