public with sharing class AuraUtils {

@AuraEnabled(cacheable=true)
public static List<SObject> databaseQuery(String queryString){
    List<SObject> returnValue;
    try{
        returnValue = Database.query(queryString);
    } catch ( Exception e ){
        throw new AuraHandledException(e.getMessage());
    }
    return returnValue;
}

import { LightningElement, api, wire, track } from 'lwc';
import databaseQuery from '@salesforce/apex/AuraUtils.databaseQuery';

export default class UtilityDemo extends LightningElement {

    @wire(databaseQuery, {queryString: '$accountQueryString'})
    accounts;

    get accountQueryString () {
        return "SELECT Id, Name, Phone, (SELECT Id , FirstName, LastName FROM Contacts) FROM Account LIMIT 20";
    }
}