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

CMakeLists.txt

@@ -1,7 +1,5 @@
 cmake_minimum_required(VERSION 3.20)
 
-set(CMAKE_PROJECT_INCLUDE_BEFORE ${CMAKE_CURRENT_SOURCE_DIR}/cmake/ClioVersion.cmake)
-
 project(clio VERSION ${CLIO_VERSION} HOMEPAGE_URL "https://github.com/XRPLF/clio"
         DESCRIPTION "An XRP Ledger API Server"
 )