Add a possibility for bulk reservations for equipment

[Gunvor4]

When printers need to be maintained or when there is a course at the workshop, it could be nice to have the possibility to "bulk reserve" printers or workspaces (or other kinds of equipment) for the event.

[elisakiv]

Could be useful to seperate between bulk reservations visitors can make(workspaces when large groups are using the workshop), and bulk reservations only MAKE members can make(3D printers etc)