Option to install a header, but don't include it in master header

[chapulina]

🎉 New feature

Summary

Add an option to ign_install_all_headers so that a header is installed, but not included in the master header.

I need this feature because I introduced a bunch of warnings to everyone who includes msgs.hh when I deprecated SuppressWarning.hh in

• Use SuppressWarning from ign-utils gz-msgs#243

Test it

TODO

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
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[scpeters]

this parameter name is confusing to me

an alternative approach is to use EXCLUDE_FILES and then manually install the desired headers, as we don in sdformat:

• https://github.com/ignitionrobotics/sdformat/blob/sdf12/include/sdf/CMakeLists.txt#L1-L8

it could benefit from an easier install helper so it doesn't need to pass ${IGN_INCLUDE_INSTALL_DIR_FULL}/${PROJECT_INCLUDE_DIR} as the destination

ign_install_includes will provide the first half of that path, but you'd still have to pass ${PROJECT_INCLUDE_DIR}

[chapulina]

Ahh much better, thanks!