Administration screens could use some helpers / framework to reduce duplication

Administration screens could use some helpers / framework to reduce duplication. It should be easy to create list, view, create, edit, delete functionality and almost oneliner for new fields.

See for example what was implemented to categories and the duplication that exists in `build-request`, `valid-request?`, various fields and buttons.

Start by examining the existing implementation for categories and compare it with the duplication in `build-request`, `valid-request?`, fields, and buttons. Map the repeated list, view, create, edit, and delete behavior before proposing a reusable approach. Done means the administration screens can share the intended helpers or framework without losing their existing functionality.

Written by the indexing model from the issue text.