Implement parallelization in bloom_build component

[emadolsky]

Is your feature request related to a problem? Please describe.
We have tenants that have tens of terrabytes of data per day. Building blooms for these tenants require a lot of resource, but each of bloom_build components is only able to utilise one cpu core as there is no parallelization in place. So the only way to overcome this issue is to deploy a huge number of small pods with one core cpu to satisfy the needs. But since we use Simple Scalable Deployment mode, scaling out bloom_build means scaling out backend component which makes the issue more complex and annoying.

Describe the solution you'd like
Having multiple workers per bloom_build to process planned tasks.

Describe alternatives you've considered
Scaling out with small pods which means 100 pods for 100 cores which is unpleasant.