Fix cmake cmp0175 warnings on cmake 3.31 and higher

[Tecnologic]

I use cmake 4.0 and gcc 14.2 on my project. the hole cmake build is based on the cmake example project.

What does thid fix?:

1. CMake starting from 3.31 have the cmp0175 policy which deprecateds the USE_TERMINAL flag for custom output commands. To fix that i changed the Comands generated in ModmConfiguration.cmake to the approach cmake suggests. currently it works for the build but i have done very little testing on the commands if everything works as expected.
2. My CMake root and the modm root are differnent folders. To make that possible i needed to change how project_source_dir is filled and that it is used for the linker script as well. Also the python path needed to change to the "CMAKE_CURRENT_SOURCE_DIR" because thats inside the generated modm folder.

[Tecnologic]

as expected most of the problems arise from folder structure.
my linker script location is "{project_source_dir}/link/linkerscript.ld" as opposed to "modm/link/linkerscript.ld". The variable {project_source_dir} seems unappropriate here.

[Tecnologic]

To get away with the linkerscript on cortex m platforms i use link/linkerscript.ld That fixes my compile issue in my project while keeping the examples working.

[Tecnologic]

I'll skip the directory independance for this pull request and stick to the override option for the linkerskript.

[salkinium]

So Point 1 makes sense to me, thanks for updating our CMake to the latest standard!

Point 2 is a bit unclear to me. Could you provide the folder structure, maybe using an simplified tree command? Why is the linkerscript location so special? Shouldn't other paths also break when moving files around? There's also a modm:platform:cortex-m:linkerscript.override option in case you want to modify the existing linkerscript.

lbuild/modm has the option to relocate the output path using the <outpath>...</outpath> xml option:

modm/examples/nucleo_f103rb/blink/project.xml

Line 7 in 464c35f

<outpath>../generated/blink</outpath>

It's a fairly niche feature that was introduced in this PR. That was before the CMake generator existed, so not sure if that is properly supported.

[Tecnologic]

I switched to using modm:platform:cortex-m:linkerscript.override option option in my project so this contains no path releated stuff anymore accept from the cmake specific stuff.

as recomended in the other pr i squashed the commits and rebased on the current release.

I hope this is fine for u.

[salkinium]

I was able to reproduce this behaviour with cmake v4.0.3 and your commit fixes it!

Thank you!

[salkinium]

Could you fix your commit message to [cmake] Fix CMP0175 warnings for CMake ≥v3.31. The current squashed one is very non-descriptive. I unfortunately cannot push to your branch.

[Tecnologic]

I struggled a bit, but i think this i gona work