Add `zero!` and `concatenate` #7

Job	Run time
IntegrationTest (DiagonalArrays) / DiagonalArrays	4m 44s
IntegrationTest (BlockSparseArrays) / BlockSparseArrays	16m 48s
IntegrationTest (ITensorBase) / ITensorBase	3m 9s
IntegrationTest (SparseArraysBase) / SparseArraysBase	4m 14s
IntegrationTest (NamedDimsArrays) / NamedDimsArrays	6m 15s
IntegrationTest (KroneckerArrays) / KroneckerArrays	12m 59s
IntegrationTest (ITensorNetworksNext) / ITensorNetworksNext	10m 43s
	58m 52s

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