Add intake subsystem

[gordonbchen]

Description

Add intake subsystem.

Type of change

• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Bugfix (non-breaking change which fixes an issue, add DEF # above in description)
• Environment change (changes to developer environment or CI configuration)
• Documentation Update (if none of the other choices apply)

How Has This Been Tested?

Tested by running intake.

Author Checklist:

• I have performed a self-review of my code
• I have added 1-2 reviewers
• I have @mentioned relevant non-reviewers as an FYI
• I have included a detailed description of my changes and their motivations