feat: serving and tracking endpoint for Numaflow

[vigith]

Initial code commit for the serving endpoint for Numaflow. A series of changes are required via followup PRs before we can make it production ready.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 56.93%. Comparing base (8da7c22) to head (f0b25ac).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1765      +/-   ##
==========================================
- Coverage   56.99%   56.93%   -0.07%     
==========================================
  Files         218      218              
  Lines       17581    17581              
==========================================
- Hits        10021    10010      -11     
- Misses       6709     6721      +12     
+ Partials      851      850       -1     

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