meson/ninja: add setup hooks (#28444)

* Add setupHook for meson/ninja build

* libhttpseverywhere: Use meson/ninja setupHooks

* jamomacore: Remove superfluous ninja buildInput

* Remove obsolete ninja buildPhases

These are all handled by ninja's setup hook.

* lean2, xcbuild: fix build with ninja setup hook

Ninja is a runtime dependency here. However, cmake can generate Ninja
build files as well to satisfy the setup hook.

* qtwebengine: fix build with ninja setup hook