Add nix build steps

[jonringer]

Nix can build on any linux distro, macos, and many others.

[johantiden]

This has some missing dependencies. Run with --pure to make sure you're not using your own environment!

❯ nix-shell --pure -p pkg-config cmake libconfig libevdev systemd

[nix-shell:~/git/johantiden/logiops/build]$ cmake -DCMAKE_BUILD_TYPE=Release ..
-- The C compiler identification is GNU 12.3.0
-- The CXX compiler identification is GNU 12.3.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /nix/store/zlzz2z48s7ry0hkl55xiqp5a73b4mzrg-gcc-wrapper-12.3.0/bin/gcc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /nix/store/zlzz2z48s7ry0hkl55xiqp5a73b4mzrg-gcc-wrapper-12.3.0/bin/g++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Could NOT find Git (missing: GIT_EXECUTABLE)
LogiOps Version Number: null
-- Found PkgConfig: /nix/store/ifr6srqgpvygd5vp14748d109ri31isv-pkg-config-wrapper-0.29.2/bin/pkg-config (found version "0.29.2")
-- Checking for module 'gio-2.0'
--   No package 'gio-2.0' found
CMake Error at /nix/store/5h0akwq4cwlc3yp92i84nfgcxpv5xv79-cmake-3.26.4/share/cmake-3.26/Modules/FindPkgConfig.cmake:607 (message):
  A required package was not found
Call Stack (most recent call first):
  /nix/store/5h0akwq4cwlc3yp92i84nfgcxpv5xv79-cmake-3.26.4/share/cmake-3.26/Modules/FindPkgConfig.cmake:829 (_pkg_check_modules_internal)
  src/ipcgull/CMakeLists.txt:16 (pkg_check_modules)


-- Configuring incomplete, errors occurred!

[johantiden]

I added this PR before I saw that this PR already existed. We should work together! I'll close mine for now.
#418