Calculate sum of squares: sum_ij X_ij^2.

::

 sumsqr(DM X) -> DM
 sumsqr(SX X) -> SX
 sumsqr(MX X) -> MX

Extra doc: https://github.com/casadi/casadi/wiki/L_1bq

Doc source: https://github.com/casadi/casadi/blob/develop/casadi/core/generic_matrix.hpp#L429

Implementation: https://github.com/casadi/casadi/blob/develop/casadi/core/generic_matrix.hpp#L429-L431

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