Adding a "Next release" milestone in trac

[Eben Eliason]

The time has come to slog through all of the tickets in trac, to
prioritize the bugs that need to get fixed in the near future, and to
push those that can wait out a bit.  I had made it as far as the first
ticket in the list before I began wishing that I could meaningfully
differentiate between the "Future release" and non-existent "Next
release" components. A "next release" component would provide a
staging ground of sorts, both preventing tickets which aren't going to
make the current release from getting pushed out into the vast Sea of
"Future Release", and providing a space for meaningfully triaging new
tickets which we don't want to lose track of, but which arrive too
late in the game to add to the "current release" roadmap.

I propose "next release" as the component name literally, such that we
don't need to forecast the next build precisely by number (ie. we
don't need to decide Right Now that the next release will be called
9.1.0 or something else).  Using a generic component allows us to keep
track of the leading edge of all open tickets, and then move tickets
back and forth between the "next release" and current release (eg.
8.2.0) components as necessary.

Comments on the effectiveness of this approach are most welcome.  Thanks!

- Eben

PS.  While we're at it, we should probably eliminate the Future
Features component and mark those tickets Future Release instead.   Is
there a differentiating factor there I'm unaware of?  Thanks!