Static Asset Service - Phase 2

[joepavitt]

Description

Task list taken from Phase 1

### Out of Scope
- [ ] https://github.com/FlowFuse/flowfuse/issues/4558
- [ ] https://github.com/FlowFuse/flowfuse/issues/4557
- [ ] Versioning of files when creating snapshots
- [ ] Managing files whilst instance is suspended

See also:

• https://github.com/FlowFuse/flowfuse/issues/3790

Which customers would this be available to

None