New SearchAlgorithm class

[felipeelia]

Is your enhancement related to a problem? Please describe.

The solution outlined below is the first step toward #2086.

Right now we have at least 3 different search algorithms. In post searches (here) it can be selected using the ep_search_algorithm_version filter but for Users and other indexable (here) it is not easily changeable.

Creating a class with the following attributes/methods would make it easier to add new algorithms and allow the user to select them (also developers would simply create a new class and use a filter to set EP to use it.)

• Name
• Description
• Search Algorithm (receiving a search term and an array of fields and returning the array to be used in the ES query)

In this first moment, we do not need any additional UI or changes in the current behavior. It is supposed to be just the build of an underlying layer for future iterations.