Consistent parameter estimation throughout the norm family

[gerkovink]

Parameter estimation in norm.boot, norm.nob and norm.pred is now done with mice::estimice() instead of the deprecated ridge regression.

[stefvanbuuren]

Thanks. That's a good clean up. I still get

Codoc mismatches from documentation object 'mice.impute.norm.predict': mice.impute.norm.predict
Code: function(y, ry, x, wy = NULL, ...)
Docs: function(y, ry, x, wy = NULL, ridge = 1e-05, ...)
Argument names in docs not in code:
ridge

[gerkovink]

fixed