[WIP] HelpdeskFramework

Trac ticket: https://trac.vikingco.com/ticket/6187

TODO list:

- [ ] Base Bootstrap structure
- [ ] Base class: BackOfficeBase
- [ ] Base class: BackOfficeObject
- [ ] Base class: BackOfficeView
- [ ] Login / logout
- [ ] Permission checking
- [ ] REST API for frontend
- [ ] Search index
- [ ] Search gui
- [ ] Rendering of BackOfficeObject
- [ ] Rendering of BackOfficeView