Advanced transformation integration for forward migration

[shreyakhajanchi]

Tests run:

1. Minimal downtime migration via sharded flow
2. Minimal downtime migration via non-sharded flow

UI:

[codecov]

Codecov Report

Attention: Patch coverage is 52.94118% with 8 lines in your changes missing coverage. Please review.

Project coverage is 45.95%. Comparing base (e49e4f1) to head (91f323d).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #855      +/-   ##
==========================================
+ Coverage   45.43%   45.95%   +0.52%     
==========================================
  Files         166      166              
  Lines       21639    21656      +17     
  Branches      515      515              
==========================================
+ Hits         9832     9953     +121     
+ Misses      11246    11140     -106     
- Partials      561      563       +2     

Components	Coverage Δ
backend-apis	45.14% <100.00%> (+1.05%)	⬆️
backend-library	52.14% <27.27%> (+0.33%)	⬆️
cli	5.14% <ø> (ø)
frontend	33.90% <100.00%> (+0.50%)	⬆️

Files	Coverage Δ
profiles/source_profile.go	87.03% <ø> (ø)
ui/src/app/app.constants.ts	100.00% <ø> (ø)
...omponents/dataflow-form/dataflow-form.component.ts	100.00% <100.00%> (+70.83%)	⬆️
...s/prepare-migration/prepare-migration.component.ts	16.78% <ø> (ø)
webv2/web.go	6.88% <100.00%> (+6.19%)	⬆️
streaming/streaming.go	16.95% <27.27%> (+6.64%)	⬆️