Add bigquery_to_bigtable yaml blueprint example and e2e test

[derrickaw]

1. Part of Phase 6 - [Task]: YAML - E2E example pipelines for common use cases #35030

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 79.73%. Comparing base (76f6e6d) to head (39fa771).
⚠️ Report is 141 commits behind head on master.

Additional details and impacted files

@@              Coverage Diff              @@
##             master   #40472       +/-   ##
=============================================
+ Coverage     56.16%   79.73%   +23.56%     
=============================================
  Files          1124      487      -637     
  Lines        178336    82289    -96047     
  Branches       1489        0     -1489     
=============================================
- Hits         100170    65615    -34555     
+ Misses        75645    16674    -58971     
+ Partials       2521        0     -2521     

Flag	Coverage Δ
go	?
java	?
python	79.73% <ø> (+0.18%)	⬆️

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[github-actions]

Assigning reviewers:

R: @tvalentyn for label python.
R: @chamikaramj for label yaml.

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