quotient/remainder for multivariate laurent polynomials

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Implement `quo_rem` for `LaurentPolynomial_mpair`.

Component: **algebra**

Author: **Daniel Krenn**

Branch/Commit: **[`ac23b38`](https://github.com/sagemath/sagetrac-mirror/commit/ac23b388d15ebeb916bd8520cd6e9de26f07eb3a)**

Reviewer: **Travis Scrimshaw**

_Issue created by migration from https://trac.sagemath.org/ticket/21968_

