Add inplace `mul!` with `StandardBasisVector`

[bartvanerp]

Currently we can only perform multiplications with the StandardBasisVector by creating a new vector/matrix. For performance reasons it might be beneficial to also support inplace operations here.

[bartvanerp]

Also check for *(Adjoint{ T, StandardBasisVector{T}}, AbstractMatrix) and extend get/set for Adjoint

[bvdmitri]

Related #344

[bvdmitri]

Can we replace the entire thing with FillArrays and its OneElement?

[bartvanerp]

Didn't know about this package, but I think yes

[bartvanerp]

Just had a look at OneElement. I like their definition where they save the axes in the struct, where we constrain ourselves to the length. Nonetheless, they seem to lack some important functionality in terms of (triple) dot-products.

[bvdmitri]

Nonetheless, they seem to lack some important functionality in terms of (triple) dot-products.

Maybe we can make a PR for them?