Fix macos build

[clonker]

There were some problems in the macos CI build.

• Starting with jsoncpp which could easily be solved by removing it, it doesn't seem like it is used anywhere anymore. (as seen here Add support for upcoming Boost 1.88.0 #15976)
• Then some issues came up with includes from boost. Usually, as these are imported / found targets, they should be treated as system libraries (which they also are, also on the failing jobs (as seen here Mask generator optimizations #15935). It seems to be a compatibility issue of CMake 4.0.0 with Apple Clang 15. Downgrading it resolved the issue but this can only be a temporary fix, if at all.
• Finally CMake 3.30 deprecated FindBoost with CMake-vendored find package script, instead they prefer to rely on a Boost cmake config (see CMP0167), which is delivered since Boost 1.70. On MacOS and Linux we have Boost 1.67 as minimum version and for CMake it is 3.13, so the whole thing is conditional.