Remove properscoring dependency in MESMER-X

[veni-vidi-vici-dormivi]

This is the only line in the MESMER Codebase that uses proper scoring. In favor of keeping the number of external dependencies small can we consider replacing this with something else? For example https://docs.scipy.org/doc/scipy/reference/generated/scipy.integrate.quad.html?

mesmer/mesmer/mesmer_x/train_l_distrib_mesmerx.py

Lines 1526 to 1534 in 32a5eb0

	tmp_cprs.append(
	ps.crps_quadrature(
	x=self.data_targ[i],
	cdf_or_dist=distrib,
	xmin=-10 * np.abs(self.data_targ[i]),
	xmax=10 * np.abs(self.data_targ[i]),
	tol=1.0e-4,
	)
	)