[For MSFT Team Review] Compute Size background service

Type of change

• Bug Fix
• Feature
• Pipeline
• Test
• Documentation

Does this introduce a change in the core logic?

• No
• Yes

Does this introduce a change in the cloud provider implementation, if so which cloud?

• AWS
• Anthos
• Azure
• GCP
• IBM

Does this follow conventional commits spec?

• No
• Yes

Have you set the target Milestone?

• No
• Yes

Have you set the no-detached-pipeline label?

• No
• Yes

Updates description?

This MR introduces a background service for computing dataset sizes. It fetches the messages from the Redis queue and processes them:

• retrieves blob sizes and calculates the dataset size
• if the size changed executes a partial update CosmosDB metadata store for the dataset

Plese not it's an MR for internal review for MSFT team.

Locking the dataset for write will be added in the next MR.