Add "or" operator handler for refine filters

[salihozdemir]

Hey @rturan29 ,

refine will soon release a version that will add support for the or operator for filtering. With the new version, CrudFilters will consist of two separate union types, so the getFilterQuery function will need to handle these two types.

The user will can create a filter as follows:

filter = [
    {
      operator: "eq",
      field: "age",
      value: 20
    },
    {
      operator: "or",
      value: [
        {
          field: "title",
          operator: "eq",
          value: "Test",
        },
        {
          field: "description",
          operator: "eq",
          value: "Test"
        }
      ]
   }
]

Here the query would look like "age" == 20 AND ("title" == "Test" OR "description" == "Test")

The field property will can be undefined so I made a small change to the your getFilterQuery function. When refine releases the new version, you can make some changes on this PR to add "or" operator support.

You can check out the PR for more information about the new release.

If you need any help, feel free to reach out to me on discord.
Happy coding!