Until 2.4.0 is released, the project version should stay at 2.3.0.
Otherwise, the project version would mismatch with that obtained via
`git describe --tags --dirty`.
This is meant to replace the dynamic generation of a version control
file called version.xml, as well as the xmlversion command line tool,
wth a static, line-separated list of files that the engine can use to
parse the version numbers.
This commit removes the dependency against custom macros, in favour of
standard CMake commands, as well as removing the use of glob expressions
since they are assumed as deprecated. [1]
[1]: https://cmake.org/cmake/help/latest/command/file.html#glob
