Lanczos Solver with COO input

[aamijar]

Lanczos solver should be able to accept COO input (currently only supports CSR input).

The code changes should luckily be minimal since the code where we use the sparse input can be kept as is. The sparse operations in the solver are spmv and leverage cusparse.

Since the behavior of the solver functions don't change based on sparse input types we should be able to add the sparse input as a template type, instead of for example using a function overload.