First approach CI for GitHubActions and first testsuite

[Alex0vSky]

Done, in accordance with #29.

• Location: tests/*.
• Without storing ThirdParty directory in repo, without "git submodules" for gtest+gmock
• Our own "main"
• Combinations:

Toolset	MSVC	LLVM
Arch	x86	x64
C++ Version	/std:c++14	/std:c++17	/std:c++20

With this configuration of combinations, operating time: 4-6 minutes.


I found out that MSVC 2022 does not officially have C++ standard number 23 yet. This means that /std:c++23 will not work.

Todo:

• /std:c++23
• Combinations

Debug	_DEBUG	nope
Optimization	/Od	/GL /O2(/Ox) /LTCG

You can use the actionlint tool to check the syntax of *.yml gha workflow before uploading to the server. There's a lot of regular PowerShell in the workflow. Workflow now triggers on push and manual launch, but excludes push triggers on the path README.md and LICENSE. The workflow code is in the file ./.github/workflows/workflow.yml.
There is gha main page.
In the future, we will be able to display a badge about successfully completed CI on the main page.

It was usefull to find #35.

[smalti]

Done, in accordance with #29.

Thank you for your effort and time in making this contribution! It looks good! )

In the future, we will be able to display a badge about successfully completed CI on the main page.

Of course, visually it will be a sign of the quality of the code :)