Creating the coverage option to ninja previously didn't work reliably.
This change re-orders the parameters passed to `meson setup` and seems
to work better. Additionally this change refactors the scripts and makes
use of `builder_run_action`.

Since keyman-system-service is a dependency of ibus-keyman it gets
build when ibus-keyman gets build. However, in that case the `--coverage`
flag doesn't get passed through in which case the `coverage-html`
target is missing from ninja. This change fixes this problem by checking
if ninja has the `coverage-html` target. If not we remove the output
directory which causes the configure action to run again with the
`--coverage` option.