R1:7f13e8a5c576

Workboards - remove 7 column restriction

Summary: Fixes T4914. We currently have a finite limit on column displays which caused T4914. This fixes T4914 by no longer using a fluid layout. Rather, we use a fixed column width layout which does not have a 7 column limit. Future work - see T4054 for an example - will likely make the fluid layout thing work with infinite columns, and / or other work may re-jigger project workboards directly.

Test Plan: had a project like in T4914 that wouldn't load and it…