Remove unused QueryBuilderService (#2104)

**Issue number:** #2068 

**What:**
- removed unused query-builder service files
  - medusa/src/services/query-builder.js
  - medusa/src/services/__mocks__/query-builder.js
- deleted export from medusa/src/services/index.ts
- (extra) deleted documentation files related to QueryBuilderService (QueryBuilderService.md)

packages/medusa/src/services/__mocks__/query-builder.js

@@ -1,11 +0,0 @@
-export const QueryBuilderServiceMock = {
-  buildQuery: jest.fn().mockImplementation(data => {
-    return Promise.resolve()
-  }),
-}
-
-const mock = jest.fn().mockImplementation(() => {
-  return QueryBuilderServiceMock
-})
-
-export default mock

packages/medusa/src/services/index.ts

@@ -27,7 +27,6 @@ export { default as ProductCollectionService } from "./product-collection"
 export { default as ProductService } from "./product"
 export { default as ProductTypeService } from "./product-type"
 export { default as ProductVariantService } from "./product-variant"
-export { default as QueryBuilderService } from "./query-builder"
 export { default as RegionService } from "./region"
 export { default as ReturnReasonService } from "./return-reason"
 export { default as ReturnService } from "./return"

packages/medusa/src/services/query-builder.js

@@ -1,52 +0,0 @@
-import { BaseService } from "medusa-interfaces"
-import _ from "lodash"
-
-class QueryBuilderService extends BaseService {
-  buildQuery(params, properties) {
-    const textSearch = _.pick(params, ["q"])
-    const filters = _.pick(params, properties)
-
-    const textQuery = this.buildTextSearchQuery(textSearch, properties)
-    const filterQuery = this.buildFilterQuery(filters)
-
-    if (textQuery && filterQuery) {
-      return {
-        $and: [textQuery, filterQuery],
-      }
-    } else if (!textQuery && filterQuery) {
-      return filterQuery
-    } else if (textQuery && !filterQuery) {
-      return textQuery
-    } else {
-      return {}
-    }
-  }
-
-  buildFilterQuery(filters) {
-    if (_.isEmpty(filters)) {
-      return
-    }
-
-    const filterQuery = {}
-
-    Object.keys(filters).map((filter) => {
-      filterQuery[filter] = filters[filter]
-    })
-
-    return filterQuery
-  }
-
-  buildTextSearchQuery(search, searchProperties) {
-    if (_.isEmpty(search)) {
-      return
-    }
-
-    const searchQuery = searchProperties.map((s) => ({
-      [s]: new RegExp(search.q, "i"),
-    }))
-
-    return { $or: searchQuery }
-  }
-}
-
-export default QueryBuilderService