devilry_subjectadmin...detailedperiodoverview: Skeleton.
devilry_subjectadmin...detailedperiodoverview: Load all data.
devilry_subjectadmin...detailedperiodoverview: Load grid UI.
devilry_subjectadmin...detailedperiodoverview: Support searching when name in NULL.
devilry_subjectadmin...detailedperiodoverview: Support sorting when name is NULL.
devilry_subjectadmin...detailedperiodoverview: Usable.

This is basically all we need for #303, but we will optimized the layout for many assignments and small displays before closing the issue.
devilry_subjectadmin...detailedperiodoverview: Link from period overview.
devilry_subjectadmin...detailedperiodoverview: Min width in the grid cols.
devilry_subjectadmin...detailedperiodoverview: Lock the name-column.

Closes #303.