feat: Watermark Implementation for Async Data Movement

[yhl25]

fixes #2365

[codecov]

Codecov Report

Attention: Patch coverage is 92.89204% with 291 lines in your changes missing coverage. Please review.

Project coverage is 69.71%. Comparing base (d4e5859) to head (4548fa3).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...t/numaflow-core/src/watermark/processor/manager.rs	82.45%	80 Missing ⚠️
rust/numaflow-core/src/watermark/isb/wm_fetcher.rs	92.94%	54 Missing ⚠️
...numaflow-core/src/pipeline/isb/jetstream/writer.rs	81.67%	35 Missing ⚠️
rust/numaflow-core/src/pipeline.rs	83.12%	27 Missing ⚠️
rust/numaflow-core/src/config/pipeline.rs	91.70%	17 Missing ⚠️
rust/numaflow-core/src/tracker.rs	85.36%	12 Missing ⚠️
rust/numaflow-core/src/message.rs	74.41%	11 Missing ⚠️
...numaflow-core/src/pipeline/isb/jetstream/reader.rs	89.00%	11 Missing ⚠️
rust/numaflow-core/src/watermark/isb.rs	97.48%	11 Missing ⚠️
.../numaflow-core/src/watermark/processor/timeline.rs	96.59%	10 Missing ⚠️
... and 9 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2376      +/-   ##
==========================================
+ Coverage   68.14%   69.71%   +1.56%     
==========================================
  Files         352      361       +9     
  Lines       46527    49934    +3407     
==========================================
+ Hits        31708    34813    +3105     
- Misses      13737    14045     +308     
+ Partials     1082     1076       -6     

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[vigith]

revert

[vigith]

why not empty string?