vo_opengl: deprecate sub-options, add them as global options

vo_opengl sub-option were always rather annoying to handle. It seems
better to make them global options instead. This is simpler and easier
to use. The only disadvantage we are aware of is that it's not clear
that many/all of these new global options work with vo_opengl only.

--vo=opengl-hq is also deprecated.

There is extensive compatibility with the old behavior. One exception is
that --vo-defaults will not apply to opengl-hq (though with opengl it
still works). vo-cmdline is also dysfunctional and will be removed in a
following commit.

These changes also affect opengl-cb.

The update mechanism is still rather inefficient: it requires syncing
with the VO after each option change, rather than batching updates.
There's also no granularity (video.c just updates "everything", and if
auto-ICC profiles are enabled, vo_opengl.c will fetch them on each
update).

Most of the manpage changes were done by Niklas Haas <git@haasn.xyz>.