Set the time step as a reference

[miguelmaso]

Removed the time step argument from the energy call. It is now a reference that can be set into the constitutive model.

There is a new function set_time_step!, to make sure there is a uniform API over all the constitutive models. The reason for adding this function is t oavoid iterating all the branches in the generalized Maxwell model.

[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	main	410d6c2...	main / 410d6c2...
Constitutive models/Visco-elastic Ψ	0.0504 ± 0.021 ms	0.051 ± 0.02 ms	0.987 ± 0.57
Constitutive models/Visco-elastic ∂Ψu	0.0627 ± 0.011 ms	0.0645 ± 0.0048 ms	0.972 ± 0.19
Constitutive models/Visco-elastic ∂Ψuu	0.111 ± 0.023 ms	0.112 ± 0.016 ms	0.987 ± 0.25
Simulations/StaticMechanicalDirichlet	0.223 ± 0.014 s	0.225 ± 0.018 s	0.989 ± 0.1
Simulations/StaticMechanicalNeumann	0.161 ± 0.016 s	0.165 ± 0.017 s	0.976 ± 0.14
Simulations/ViscoElastic	8.38 s	8.68 s	0.965
Tensor algebra/Cofactor	0.063 ± 0.002 μs	0.063 ± 0.002 μs	1 ± 0.045
Tensor algebra/Det(A)Inv(A')	0.124 ± 0.006 μs	0.121 ± 0.005 μs	1.02 ± 0.065
Tensor algebra/δδ_λ_2d	19 ± 1 ns	19 ± 1 ns	1 ± 0.074
Tensor algebra/δδ_μ_2d	19 ± 1 ns	19 ± 1 ns	1 ± 0.074
time_to_load	2.38 ± 0.018 s	2.41 ± 0.0079 s	0.988 ± 0.0081

Memory benchmarks

	main	410d6c2...	main / 410d6c2...
Constitutive models/Visco-elastic Ψ	1.25 k allocs: 0.0794 MB	1.25 k allocs: 0.0789 MB	1.01
Constitutive models/Visco-elastic ∂Ψu	1.37 k allocs: 0.0917 MB	1.37 k allocs: 0.0911 MB	1.01
Constitutive models/Visco-elastic ∂Ψuu	2.31 k allocs: 0.158 MB	2.33 k allocs: 0.158 MB	1
Simulations/StaticMechanicalDirichlet	1.59 M allocs: 0.114 GB	1.59 M allocs: 0.114 GB	1
Simulations/StaticMechanicalNeumann	1.41 M allocs: 0.0901 GB	1.41 M allocs: 0.0901 GB	1
Simulations/ViscoElastic	0.127 G allocs: 8.28 GB	0.128 G allocs: 8.25 GB	1
Tensor algebra/Cofactor	1 allocs: 0.0781 kB	1 allocs: 0.0781 kB	1
Tensor algebra/Det(A)Inv(A')	4 allocs: 0.25 kB	4 allocs: 0.25 kB	1
Tensor algebra/δδ_λ_2d	0 allocs: 0 B	0 allocs: 0 B
Tensor algebra/δδ_μ_2d	0 allocs: 0 B	0 allocs: 0 B
time_to_load	0.149 k allocs: 11.1 kB	0.149 k allocs: 11.1 kB	1

[miguelmaso]

@jmartfrut as commented before, I'll revert all the changes related to lambda to reduce the cope of this PR