Add contains operation when list filetring #29

When we are using list to filter (with contains), the translations of expression is similar to:

... WHERE field IN ('value1', 'value2') ...

Suggestion:
Has a new type in WhereOperator

Change and add validations in ExpressionFactory class

Add new case in switch of GetExpression method in FiltersExtensions class

Create method to build expression:

Use case example (updating RestFulTests):

I opened one PR with the updates #30