Document how staging environment is used

[sdhoyt]

Summary
Data processing software will need to be fully tested in the staging environment prior to being integrated into the SDC production processing environment. The staging environment replicates that of production, but operates independently in order to not interfere with daily production. This process for how the staging environment will be used should be documented.

Parent Requirement

SOC-SDC-L4-27	SDC Staging Environment	The SDC shall provide a staging environment for developer testing of L1, L2, L3, and i-ALiRT software prior to release to production.	Requirement	Data processing software will need to be fully tested in the staging environment prior to being integrated into the SDC production processing environment. The staging environment replicates that of production, but operates independently in order to not interfere with daily production.	SOC-L3-57	Demonstration

[sdhoyt]

Documentation for setting up and deploying the staging environment was done here: https://sds-data-manager.readthedocs.io/en/latest/cdk/index.html