Update CI scripts (deal with deprecated OS versions)

[SergiusTheBest]

• Extracted reusable workflow: Created a new .github/workflows/build.yml as a reusable workflow to eliminate code duplication
• Container-based builds: Introduced Docker container support for older GCC/Clang versions using Conan.io images instead of managing Ubuntu package repositories
• Eliminated direct Ubuntu 20.04 usage from the CI matrix
• GCC versions: Maintained support for GCC 4.8, 5, 7, 9, 11, and 14 through container images
• Clang versions: Updated to include Clang 18 and maintained Clang 6.0 support via containers
• Windows builds: Updated to use Visual Studio 2022 with both x86 and x64 architectures (removed VS2019 due to GitHub runner deprecation)
• Updated FreeBSD versions:
  • freebsd-13-3 → freebsd-13-5
  • freebsd-14-0 → freebsd-14-3
  • Maintained freebsd-15-0-snap for bleeding-edge testing