"Check all review types that apply"

[Jeroen T. Vermeulen]

The basic use of a merge proposals is to request review from either a default or someone in particular, with an optional review type. But in Launchpad at least, we often need several types of review on a single proposal, each with their own default reviewer:

 code—from the launchpad engineering team
 ui—from the UI review team
 db—from two people who act as a team
 production-change—from people who act as a team

It'd be great if the MP form could offer us all these review types with their default reviewers pre-set, and let us "check all that apply."