Simplify consent UI onboarding [design doc]

[allisonking]

Is your feature request related to a specific problem?

We need to simplify our onboarding for consent only customers.

Describe the solution you'd like

TBD!

Describe alternatives you've considered, if any

A description of any alternative solutions or features you've considered.

Additional context

Add any other context or screenshots about the feature request here.

[allisonking]

Broke this ticket up into the following tickets:

• Scaffold initial page for adding vendors/cookies for consent #4051
• Add a modal for adding a cookie form  #4052
• Add a modal form for adding a vendor #4053
• Add table for showing vendors and cookies #4054
• Build new data use dropdown component #4055
• Make data_categories optional #4059

[allisonking]

original design doc: https://ethyca.atlassian.net/wiki/spaces/EN/pages/2778202186/2023-09-06+Simplify+consent+UI