feat: Native CCSS Feature - Expanded Section Configuration, Empty Custom Sections, Section Rename/Delete

[kgar]

Support the following Tidy Custom Item Section specifications:

Utility Toolbar / Configuration

• Allow for adding custom sections that do not yet have items. These sections can be added in the Section Configuration UI and have decoration indicating they are added sections (as opposed to derived sections based on present items). Likewise, allow for removing custom sections.
• When removing a custom section in configuration, if the section has items, those items should have their custom section flag cleared so that they return to their default sections. As a result, custom sections that were manually added or derived from the present items can be deleted.
• Allow for renaming custom sections in Section Configuration. Any items that are assigned to that section should have their section flag updated accordingly to reflect the new name.