Remove install_rpath from installed targets

Remove install_rpath from installed targets

Specifying the RPATH deviates from widespread packaging norms where the
value isn't expected to be set by the project. [1] [2] [3]

Meet this expectation by restoring meson's default behavior where
targets in the build directory have the RPATH fixed with meson stripping
the value during installation.

[1]: https://wiki.debian.org/RpathIssue
[2]: https://docs.fedoraproject.org/en-US/packaging-guidelines/#_beware_of_rpath
[3]: https://en.opensuse.org/openSUSE:Packaging_checks#Beware_of_Rpath