feat(runtime-manager): introduce metadata database for function and container state

[sreyasppradeep1455]

Problem

Currently, the runtime manager keeps container and function state in an in-memory map (ContainerMap). While this works for development, it has several limitations:

• State is lost if the runtime manager restarts.
• Container metadata cannot be shared across multiple runtime instances.
• Function metadata (deployments, images, configuration) is not persisted.

To address these limitations, we should introduce a Metadata Database that stores function and container metadata persistently.

This database will act as the source of truth for the runtime manager.

---

Goals

Implement a metadata storage layer to persist:

• Function metadata
• Container state
• Runtime configuration