Updated CI, added CD

[mfep]

• Added .gitignore file,
• Added .clang-format (based on OpenCL-SDK's corresponding file) and format enforcing script.
• Minor changes to source files to avoid warnings on all compilers tested in CI.
  • -Werror//WX is enabled in CI
• Refactored the CMakeLists.txt to be able to produce a binary Debian package using cpack.
  • CMake minimum version is bumped to 3.16.
• Updated the CI (pre-release) script.
  • Removed the previous separate workflows for Windows, MacOS and Linux. All CI scripts reside in the presubmit workflow now.
  • Added a job that checks the changed code for formatting conformance via git-clang-format.
  • Updated Linux CI to use a new container image
    • Most jobs in the matrix are based on Ubuntu 22.04
    • Compilers gcc-11, gcc-13, clang-14, clang-16 and gcc-9 on Ubuntu 20.04
    • Binary targets: x86-64 and x86 on Ubuntu 20.04
    • C standards: 99, 11, 17
    • CMake versions: 3.26 and 3.16 on Ubuntu 20.04
    • CMake generators: Ninja Multi-Config, Unix Makefiles
    • Added the generation of the Debian package, testing the package, and testing the install tree to the workflow
  • Updated Windows CI, which runs on Windows Server 2022
    • MSVC toolsets: v141, v142, v143, clang-cl (this latter with msbuild only)
    • Binary targets: x86-64, x86
    • C standards: 99, 11, 17
    • CMake: system installed, currently 3.27
    • CMake generators: Ninja Multi-Config, Visual Studio 17 2022
    • Added the result checking of the external command invocations in the PowerShell snippets
  • Updated MacOS CI, which runs on MacOS 13
    • Compilers: Apple-Clang 14, gcc-11, gcc-13 (gcc with Ninja Multi-Config only)
    • Binary target: x86-64
    • C standards: 99, 11, 17
    • CMake: system installed, currently 3.27
    • CMake generators: Ninja Multi-Config, XCode
    • Added test checking the consumption of the install tree
  • Added Android CI, which is build only (virtualization is not available with the default GitHub runners)
    • Binary targets: x86-64, arm64
    • Android API levels: 19, 33
• Added a release workflow which triggers on the push of a v* tag
  • Added DebSourcePkg.cmake which is intended to run in CMake script mode. This script generates the debian/control, debian/changelog and ``debian/rules` files which are required to build a Debian source package.
  • The release workflow generates the Debian source package and pushes it to a prescribed Launchpad PPA. The details of the release (e.g. maintainer, signing key) has to be set up as repository variables.
  • Detailed instruction regarding the release procedure is going to be added to the OpenCL SDK repository.

This PR is considered to be complete, albeit review remarks and/or changes to related PRs might warrant minor updates.

The commits are authored by me, however a significant part of the work has been done by @Beanavil.

[CLAassistant]

All committers have signed the CLA.