Automatically archive orphaned feature segments if they are not part of any overrides

### How are you running Flagsmith

- [ ] Self Hosted with Docker
- [ ] Self Hosted with Kubernetes
- [x] SaaS at flagsmith.com
- [ ] Some other way (add details in description below)

### Describe the bug

When a feature specific segment continues to exist even when it is not associated with a feature flag anymore leading to environment document bloat. It requires users to manually clean it up after the feature has been rolled out fully which impacts UX, velocity and tech debt.

### Steps To Reproduce

1. Create new feature flag
2. Create Feature specific segment override
3. Remove the segment override
4. The orphaned segment can still be found in the list of segments (referencing the feature flag for which it was created) creating bloat even after feature is rolled out.

### Expected behavior

- The orphaned feature specific segment should be automatically archived and eventually garbage collected.
- Creating segments for frequent operations such as gradual rollout of a simple boolean is an overkill. (Gradual rollouts must be a slider option alongside the feature flag (similar to A/B test) without forcing the user to create a new segment)

The cleanest solution here is to inline the rules right next to the feature flag, instead of creating feature specific segment overrides for each feature. The goal of a segment is to be reusable across features. Feature specific segments slow down velocity and add to tech debt.

### Screenshots

_No response_