feat: Adding support for an Aggregated monitoring dashboard in sharded migration

[asthamohta]

1. Add support for an Aggregated monitoring dashboard in sharded migration
2. Store GCS Buckets associated with a stream
3. Revise certain queries for sharded and unsharded migration based on discussions

Testing

1. Sharded migration dashboard creation success
2. Non sharded migration dashboard creation success
3. Dashboard creation when fetching gcs bucket fails
4. Testing dashboard creation failure

[codecov]

Codecov Report

Merging #686 (2e48906) into master (049f8ea) will decrease coverage by 0.02%.
The diff coverage is 0.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #686      +/-   ##
==========================================
- Coverage   54.27%   54.25%   -0.02%     
==========================================
  Files          65       65              
  Lines       12351    12355       +4     
==========================================
  Hits         6703     6703              
- Misses       5181     5185       +4     
  Partials      467      467              

Components	Coverage Δ
backend-apis	43.54% <0.00%> (-0.05%)	⬇️
backend-library	60.21% <ø> (ø)
cli	0.00% <ø> (ø)
frontend	∅ <ø> (∅)

Files	Coverage Δ
internal/convert.go	65.35% <ø> (ø)
webv2/web.go	35.50% <0.00%> (-0.06%)	⬇️

[shreyakhajanchi]

LGTM