Refactor all the things

[SouthEndMusic]

I plowed trough some refactoring ideas:

• Add the node type specific index to NodeID, which is used to avoid many lookups
• Precalculate: FlowBoundary outflow edges, DiscreteControl controlled nodes
• Split the logic_mapping per DiscreteControl node
• Let DiscreteControl read and write variables via refs. This neatly cleans up what was first partly node type specific and type unstable code. The source of truth for which parameters are controllable is now in the function controllablefields in validation.jl, which can also be used to automatically generate a table of controllable parameters in the docs

[evetion]

Was your secondary goal to touch all Julia core files? 😅

[evetion]

AGV model went from:

2.030423 seconds (3.86 M allocations: 1006.978 MiB, 1.50% gc time) to 1.934420 seconds (3.02 M allocations: 966.206 MiB, 1.83% gc time)

Given the reduction in allocations, this might be even faster on non-control heavy models.