inspect-library we only care about the line based output.
With this commit we make the line based format the default and remove
the older JSON based one. The option
--line-based is still available
inspect-library to avoid any unexpected breakage and we expect to
remove it after a couple of Steam Runtime releases.
inspect-library-libelf instead, we already removed the
--line-based option because it is a new helper and there are no
Based on !540 (merged)