The conductor doc is not really end user material,
so this moves it under reference/, removes it from the
user page and adds it to the reference index for internals.
Also makes the contributor page link to the reference internals
since it's kind of weird to have one contributor section that
only mentions one thing but the internals under reference have
a lot more of that kind of detail. Finally, a todo is added so
we don't forget to update the reference internals about versioned
objects at some point since that's always a point of confusion
for people.
Change-Id: I8d3dbce5334afaa3e1ca309b2669eff9933a0104
37164b418e