Allow for longer `Role.category` values

[amcclain]

We only allow 30 chars for role categories. Not sure why we were quite so concerned with limiting to such a short string, but with the (excellent) support for slash-delimited categories it is easy to exceed:

[amcclain]

I'd propose we up this to 100 chars - that seems about as long as we would expect - e.g. an imaginary, very lengthy category like Custom App Name\Permissions\Business Units\Middle Office\Pricing Tools is ~70 chars.

Will need to:

• Add constraint to GORM mapping on domain class
• Determine SQL to modify column length for existing DBs, include in changelog
• Add client-side validation in hoist-react to match