Apply the Beman Standard to Beman.Example

[neatudarius]

Apply the Beman Standard to Beman.Example and possible more more tweaks.

Updates related to the Beman Standard - existing requirements/recommendations:

• [ ] Apply LICENSE.APPROVED.
• [ ] Apply LIBRARY_NAMES.
• [ ] Apply REPOSITORY_NAME.
• [ ] Apply DIRECTORY.INTERFACE_HEADERS.
• [ ] Apply CMAKELISTS.DEFAULT / CMAKELISTS.SKIP_TESTS

Updates related to the Beman Standard - NEW requirements/recommendations:

• [ ] Apply $ITEM_FOR_DIRECTORY_SHORTHAND
• [ ] Apply TESTS.DIRECTORY - TBD propose convention: src/Beman/$Library/tests.
• [ ] Apply TESTS.FILE_SUFFIX - TBD propose convention: *.t.cpp
• [ ] Apply LIBRARY.TARGET_NAME - TBD propose convention: beman_$library.
• [ ] Apply TESTS.TARGET_NAME - TBD propose convention: beman_$library_test.

Updates related to docs and usage example:

• [ ] Add API example: include/Beman/Example/example.hpp / src/Beman/Example/example.cpp.
• [ ] Add basic unit test and framework integration with Gtest.
• [ ] Add usage example: examples/sample_usage.cpp.

Updates related to CI/infrastructure/other missing bits:

• [ ] Extend compiler / standard version build and run on CI: C++98, C++03, C++11, C++14, C++17, C++20, C++23, C++26.
• [ ] Add .gitignore.
• [ ] Add .github/CODEOWNERS.
• [ ] Add badge with CI tests status in README.md.

[neatudarius]

Most of the issues are implemented in #15