XDB-494 fixed windows build

[MarkSh1]

• CMakeLists.txt: Move Swift language from project(LANGUAGES) to conditional enable_language(Swift) — fixes Swift not supported by Visual Studio generator
• cmake/CompileBoost.cmake: Remove EXACT from find_package(Boost ...) on Windows — fixes Boost version mismatch with vcpkg
• cmake/CompileVexillographer.cmake: Set VEXILLOGRAPHER_COMMAND in Win32 branch — fixes "VEXILLOGRAPHER_COMMAND is undefined" error
• cmake/ConfigureCompiler.cmake: Guard CMAKE_REQUIRED_LIBRARIES c with NOT WIN32 — fixes coroutine detection failure (no libc on Windows)
• flow/CMakeLists.txt: Add python.exe to venv search names — fixes python3.exe not found in venv on Windows
• packaging/msi/CMakeLists.txt: Guard fdbmonitor references — fixes "No target fdbmonitor" error
• .github/workflows/windows-boost-test.yml: Add lz4, -DBUILD_DOCUMENTATION=OFF, -DWITH_CSHARP=OFF — additional fixes