Refactor temperature annealing

Refactor temperature annealing

This refactors temperature annealing by dividing it into two subfunctions,
one which returns a new temperature, keeping the inputrec constant and
being independent of the Update object, and one which updates the inputrec
and the Update object.

This separation allows most of the code to be reused by modular simulator,
and it is also a first step towards a design which does not need to modify
the input record (#3854)

Refs #3417, #3854