Parametrize SparseMatrixCOO with vector types

[dpo]

Currently, a SparseMatrixCOO can only store explicit vectors. It would be convenient to define rows, cols and vals as views, for example in a factorization-based Levenberg-Marquardt solver, where we will factorize the augmented Jacobian

$$ \begin{bmatrix} J \\ \sigma I \end{bmatrix} $$

but we want to update $J$ and $\sigma$ separately.

I think that can be done by parameterizing the SparseMatrixCOO type with the "vector" types.

@farhadrclass