Refactor `construct_device!` pattern

[luke-kiernan]

The construct_device! pattern is starting to strain the codebase. Right now, we have roughly one method per (stage, device, device_model, network_model) combination. That's a lot of construct_device! definitions. And they largely follow a predictable pattern.

More of a meta-issue: this isn't going to be fixed by just one thing. But opening this to start putting potential fixes in one spot so they don't get lost.

[luke-kiernan]

One idea: push the multiple-dispatch down a level and add all variables/constraints/expressions etc in one swoop. Replace

# branch_constructor.jl
function construct_device!(
    # ...
    device_model::DeviceModel{T, StaticBranch},
    network_model::NetworkModel{ACPPowerModel},
) where {T <: PSY.ACTransmission}
    devices = get_available_components(device_model, sys)
    # Create the four directional flow variables
    add_variables!(container, FlowActivePowerFromToVariable, devices, StaticBranch)
    add_variables!(container, FlowActivePowerToFromVariable, devices, StaticBranch)
    # ...
end

with something like

# only pass the args that matter and only return the args that vary.
variables_to_add(::T, ::ACPPowerModel, ::StaticBranch) where {T <: ACTransmission} = 
    [(FlowActivePowerFromToVariable, StaticBranch),
     (FlowActivePowerToFromVariable, StaticBranch), ...]

then we just iterate over variables_to_add. Similarly define expressions_to_add, constraints_to_add, etc. One more layer of indirection, but the meaningful differences in behavior land in one place (you can read them off of {foo}_to_add) instead of getting lost amid the repetition.

[luke-kiernan]

Also relevant: #165