🛠️ [TASK] : Add memory metrics to improve observability

[apskhem]

Summary

We need better memory metrics, and we should add those.

Description

Add stats_alloc and memory_stats. So we can measure current memory state/usage of cat-gateway.

Define the memory metrics (just like the endpoint metrics) and it would have a thread which runs on a timer and periodically updates the memory metrics by gathering the info from the appropriate API's.