[VAL-6.0] Improvements and fixes

[Fantu]

• Add circleci config
• fix build on gcc 13.x
• add github workflow for test build of kernel module in different kernel versions
• add github workflow for test build of all
• Update and improve README

[SergeiShtepa]

@Fantu - Thanks for the help. I checked the buildability of the stable-v2 branch on ubuntu 23.10. Alas, I have a lot of urgent work right now. Therefore, I could not quickly offer my fixes for these bugs. And therefore, your contribution to the project is especially valuable.

[Fantu]

from circleci tests (that I enabled on my fork) ubuntu 23.10 build now correctly on VAL-6.0, VAL-6.1 and stable-v2 I tested also stable-v2 on debian unstable but FWIK gcc13 should now be ok also on other recent/next release of many gnu/linux distros about kernel module automatic tests I added jobs for test latest version thanks to debian unstable (except new version freeze period) so I think it will be tested enough for the latest kernels I added automatic test also on VAL-6.0 (excluding other archs) that was missed that, I think can be useful About build of library/tools/tests I'll probably have to see if I can make some improvements to test better even without circleci