feat: Release pre-requisites for Microsoft.AutoGen.Core NuGet

[lokitoth]

This is in preparation for releasing the Microsoft.AutoGen.Core NuGet package.

• Moves IHandle<> to Microsoft.AutoGen.Contracts

• Makes KVStringParseHelper internal

• Updates versions of certain dependencies

• Updates NuGet package properties

• Enables deterministic build

• Enables ContinuousIntegrationBuild in CI

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.59%. Comparing base (994c866) to head (345fe6a).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5270   +/-   ##
=======================================
  Coverage   70.59%   70.59%           
=======================================
  Files         180      180           
  Lines       11668    11668           
=======================================
  Hits         8237     8237           
  Misses       3431     3431           

Flag	Coverage Δ
unittests	70.59% <ø> (ø)

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