* Fixed a bug for build via nix, when c3c-checks and c3c-debug didn't have a git hash
* Got rid of python3 requirement for checks in nix as it's no longer needed
* Now c3c properly displays it's build date in nix build
* Add more platforms for checks in nix build
* Add installation and compilation on Nix to README
* Add support for nix flakes
* Added debug build type for flake.nix; Got rid of redundant version check in nix/default.nix
* Added dev shell with compile_commands.json into flake.nix
* Fixed issue with generated compile_commands.json while creating c3c derivation with nix. Deduced devShells in flake.nix to nix/shell.nix