Duplicate names in `NLSMeta` make `get_*` getters ambiguous

Currently for any given `NLSModel`, `get_nnzj(nls)` returns the number of nonzeros in the residual jacobian and this shadows the `get_nnzj` from the `NLPModelMeta`. I think the fields in `NLSModelMeta` should be prefixed (or postfixed, I have no strong opinions) with `residual`, or the getters defined in `nls/tools.jl` should be prefixed with `get_nls_` instead of `get_`.