refactor(services): implement the contracts directly

Both services already carry the Impl suffix, so the contract name is
free and the alias import the implements clause needed is not.

Author: edusperoni

lib/services/doctor-service.ts

@@ -8,12 +8,12 @@ import {
 	NODE_MODULES_FOLDER_NAME,
 	TNS_CORE_MODULES_NAME,
 } from "../constants";
+import { DoctorService } from "../contracts/doctor-service";
 import { doctor, constants } from "@nativescript/doctor";
 import { IProjectDataService } from "../definitions/project";
 import { IVersionsService, IOptions } from "../declarations";
 import { IPlatformEnvironmentRequirements } from "../definitions/platform";
 import {
-	IDoctorService,
 	IAnalyticsService,
 	IHostInfo,
 	IChildProcess,
@@ -27,7 +27,7 @@ import { injector } from "../common/yok";
 import { color } from "../color";
 import { ITerminalSpinnerService } from "../definitions/terminal-spinner-service";
 
-export class DoctorServiceImpl implements IDoctorService {
+export class DoctorServiceImpl implements DoctorService {
 	private static DarwinSetupScriptLocation = path.join(
 		__dirname,
 		"..",

lib/services/project-name-service.ts

@@ -1,10 +1,10 @@
 import { isInteractive } from "../common/helpers";
-import { IProjectNameService } from "../declarations";
 import { IErrors } from "../common/declarations";
 import * as _ from "lodash";
+import { ProjectNameService } from "../contracts/project-name-service";
 import { injector } from "../common/yok";
 
-export class ProjectNameServiceImpl implements IProjectNameService {
+export class ProjectNameServiceImpl implements ProjectNameService {
 	constructor(
 		private $projectNameValidator: IProjectNameValidator,
 		private $errors: IErrors,