chore: Do not generate source files and use target_compile_definition… (#2369)

…s to set version

Advantages:
- not modifying src dir in build time (`git clean` will also remove
less)
- simpler codecov (if we decide to move it to separate stage in the
future)
- The cpp file is perfectly valid, so it will be treated as a C++ files
by all the tooling
- No need to use CMAKE_PROJECT_INCLUDE_BEFORE, should work fine without
it
- Instead of generating + recompiling, we will just be doing
recompilation of 1 file

.gitignore

@@ -9,4 +9,3 @@
 .sanitizer-report
 CMakeUserPresets.json
 config.json
-src/util/build/Build.cpp