Device UI/UX improvements for managing large numbers of devices

[Steve-Mcl]

Follow up to https://github.com/flowforge/security/issues/16

Device Management would benefit from UI/UX improvements with the following observations

### Tasks
- [ ] https://github.com/FlowFuse/flowfuse/issues/3953
- [ ] https://github.com/FlowFuse/flowfuse/issues/4290
- [ ] bulk actions for instance assignment
- [ ] bulk actions for deregistration
- [ ] grouping/sorting by current snapshot
- [ ] grouping/sorting by devices in developer mode)

Originally posted by @Steve-Mcl in https://github.com/flowforge/security/issues/16#issuecomment-1614867214