Removed previous calls to Cauchy

[miguelmaso]

Second part of #56

The third step will be to implement a consistent Cauchy function

[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	main	2c76504...	main / 2c76504...
Constitutive models/Visco-elastic Ψ	0.0497 ± 0.027 ms	0.0495 ± 0.027 ms	1 ± 0.78
Constitutive models/Visco-elastic ∂Ψu	0.0644 ± 0.0042 ms	0.0648 ± 0.0037 ms	0.994 ± 0.086
Constitutive models/Visco-elastic ∂Ψuu	0.115 ± 0.017 ms	0.114 ± 0.016 ms	1.01 ± 0.2
Simulations/StaticMechanicalDirichlet	0.16 ± 0.011 s	0.163 ± 0.01 s	0.982 ± 0.093
Simulations/StaticMechanicalNeumann	0.139 ± 0.015 s	0.137 ± 0.013 s	1.02 ± 0.15
Simulations/ViscoElastic	8.4 s	8.44 s	0.996
Tensor algebra/δδ_λ_2d	30 ± 0 ns	30 ± 0 ns	1 ± 0
Tensor algebra/δδ_μ_2d	30 ± 0 ns	30 ± 0 ns	1 ± 0
time_to_load	2.58 ± 0.0062 s	2.6 ± 0.015 s	0.994 ± 0.0062

Memory benchmarks

	main	2c76504...	main / 2c76504...
Constitutive models/Visco-elastic Ψ	1.25 k allocs: 0.0794 MB	1.25 k allocs: 0.0794 MB	1
Constitutive models/Visco-elastic ∂Ψu	1.37 k allocs: 0.0917 MB	1.37 k allocs: 0.0917 MB	1
Constitutive models/Visco-elastic ∂Ψuu	2.31 k allocs: 0.158 MB	2.31 k allocs: 0.158 MB	1
Simulations/StaticMechanicalDirichlet	1.7 M allocs: 0.118 GB	1.7 M allocs: 0.118 GB	1
Simulations/StaticMechanicalNeumann	1.43 M allocs: 0.0908 GB	1.43 M allocs: 0.0908 GB	1
Simulations/ViscoElastic	0.127 G allocs: 8.28 GB	0.127 G allocs: 8.28 GB	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