Move the lazy matmuls to LazyArrays #6
Description
The overloads for default_blasmul! in lazy_matmuls.jl ensure that dense linear algebra is not used when materializing the action of the orbital Hamiltonian on a radial orbital. The correct way however, is to provide overloads for materialize!(::MulAdd{DiagonalLayout}), &c., and these should be upstreamed to LazyArrays.jl.