pynumaflow-lite: Pythonic APIs for Reducer and ReduceStreamer

[BulkBeing]

Similar to #383

See manifests/reduce/reduce_counter_class.py and manifests/reducestream/reducestream_counter.py for the usage.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.99%. Comparing base (acbb681) to head (421e5f6).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #389   +/-   ##
=======================================
  Coverage   92.99%   92.99%           
=======================================
  Files          68       68           
  Lines        3654     3654           
  Branches      236      236           
=======================================
  Hits         3398     3398           
  Misses        190      190           
  Partials       66       66           

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[vigith]

   sock_file="/tmp/var/run/numaflow/reducestream.sock",
   server_info_file="/tmp/var/run/numaflow/reducestreamer-server-info"

we should we remove these from the examples? users might copy paste and code will not run.

[BulkBeing]

   sock_file="/tmp/var/run/numaflow/reducestream.sock",
   server_info_file="/tmp/var/run/numaflow/reducestreamer-server-info"

we should we remove these from the examples? users might copy paste and code will not run.

The user facing examples are in manifests/ directory. Those examples doesn't override these parameters.
We use the above code in our integration tests where the Rust gRPC client invokes the UDFs. This is useful for users as well if they want to write integration tests.