Define Cells architecture constraints
Problem
The Cells architecture comes with a number of constraints that are only implicitly outlined in https://docs.gitlab.com/ee/architecture/blueprints/cells/ right now. This makes it hard for other groups to understand why features may need to change and in what ways.
Proposal
via @mnichols1
Add a section to the blueprint that outlines constraints that are a consequence of a Cells architecture. These could be grouped like this
Hard constraints
Actions that are forbidden or impossible to achieve
Soft constraints
Actions that are non-performant or otherwise challenging
Unconstrained
Things not impacted or work as they do today
By outlining these constraints it makes it easier for groups to understand the "framework" within which existing features would have to operate and what new features would need to take into account.