Add field attribute called "Ranking Multiplier"

[szeke]

Each field should have an attribute called Ranking Multiplier and the value can be a float number that defaults to 1.0. Internally, the attribute can be called ranking_multiplier or whatever convention we are using for attributes.

This attribute is only relevant when the type of the field is Number.

The tooltip should say: Affects search ranking by multiplying the elastic search score by value of this field times the value of the ranking multiplier.

[jasonslepicka]

There should be two UI elements for each field. One that enables the ranking multiplier field (like a check box) and then a text box for the value that defaults to 1.0 which is for the user to specify the attribute value. I've called the attribute scoring_coefficient instead of ranking_multiplier.