Added new tensor contractions

[miguelmaso]

Contractions needed for computing projections of the acoustic tensor

[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	main	574ae55...	main / 574ae55...
Constitutive models/Visco-elastic Ψ	30.8 ± 13 μs	23.3 ± 13 μs	1.32 ± 0.93
Constitutive models/Visco-elastic ∂Ψu	29.2 ± 13 μs	26.3 ± 12 μs	1.11 ± 0.73
Constitutive models/Visco-elastic ∂Ψuu	0.0501 ± 0.021 ms	0.0512 ± 0.022 ms	0.98 ± 0.59
Simulations/StaticMechanicalDirichlet	0.122 ± 0.0079 s	0.126 ± 0.0092 s	0.973 ± 0.095
Simulations/StaticMechanicalNeumann	0.109 ± 0.016 s	0.115 ± 0.015 s	0.949 ± 0.18
Simulations/ViscoElastic	10.3 s	10.2 s	1.01
Tensor algebra/Cofactor	0.054 ± 0.002 μs	0.06 ± 0.001 μs	0.9 ± 0.037
Tensor algebra/Det(A)Inv(A')	0.1 ± 0.004 μs	0.089 ± 0.004 μs	1.12 ± 0.068
Tensor algebra/δδ_λ_2d	22 ± 1 ns	22 ± 1 ns	1 ± 0.064
Tensor algebra/δδ_μ_2d	22 ± 1 ns	22 ± 1 ns	1 ± 0.064
time_to_load	2.47 ± 0.011 s	2.48 ± 0.012 s	0.997 ± 0.0068

Memory benchmarks

	main	574ae55...	main / 574ae55...
Constitutive models/Visco-elastic Ψ	0.542 k allocs: 0.0443 MB	0.542 k allocs: 0.0443 MB	1
Constitutive models/Visco-elastic ∂Ψu	0.593 k allocs: 0.0492 MB	0.593 k allocs: 0.0492 MB	1
Constitutive models/Visco-elastic ∂Ψuu	1.02 k allocs: 0.0839 MB	1.02 k allocs: 0.0839 MB	1
Simulations/StaticMechanicalDirichlet	1.51 M allocs: 0.108 GB	1.51 M allocs: 0.108 GB	1
Simulations/StaticMechanicalNeumann	1.48 M allocs: 0.0927 GB	1.48 M allocs: 0.0927 GB	1
Simulations/ViscoElastic	0.162 G allocs: 12.7 GB	0.162 G allocs: 12.7 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