Update OpenAPI documentation in GitBook

[ngachung]

We include all DS endpoints into a single GitBook page, which is confusing to end users. For example, setting up elasticsearch, auth would only be used by DS admin team and not end users. We should separate the documentation, one for users and one for admin/dev for clarity. Also, group actions by object type e.g. collections, granules, etc.

[ngachung]

Made initial pass through the docs.

Created two separate API docs page

• https://unity-sds.gitbook.io/docs/developer-docs/data/docs/users-guide/data-services-api-specification
• https://unity-sds.gitbook.io/docs/developer-docs/data/docs/admin-guide/admin-api-specification

Added headers to describe each section, e.g. "API to manage collections", "API to manage items"

Need to update API description in code and reimport updated OpenAPI spec

• Remove references to Cumulus
• Describe /am-uds-dapa/collections/{collection_id}/variables/ because it says "Get Granules Dapa"
• ...