Meson: Functionality equivalent to autotools .project files
With meson versions < 0.57 the implementation would be messy compared to fc.read() usage that meson 0.57 offers, so maybe we consider #43362 dependency of this.
Autotools is still the main build system in 3.1 + this is currently needed for freeciv-web (that's using master anyway)
Our autotools build supports fork project to define some of its properties in a .project file. Support for similar mechanism is needed in meson based builds.