Add support for ICU library bundled with Windows

[rmisev]

This adds the cmake option variable UPA_USE_WINDOWS_ICU and a preprocessor macro of the same name for this purpose:

1. For cmake CLI add the option -DUPA_USE_WINDOWS_ICU=ON
2. Or define the preprocessor macro UPA_USE_WINDOWS_ICU = 1 if you are using amalgamated sources

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 99.65%. Comparing base (c9b7de4) to head (b71aca6).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #49 +/- ## ======================================= Coverage 99.65% 99.65% ======================================= Files 16 16 Lines 2333 2333 Branches 387 387 ======================================= Hits 2325 2325 Misses 8 8 ```

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