feat(plugin): add MS App Center shared plugin (#3618)

* feat(plugin): add MS App Center shared plugin

* docs(app-center-shared): add incompatible doc

src/@ionic-native/plugins/app-center-shared/index.ts

@@ -0,0 +1,62 @@
+import { Injectable } from '@angular/core';
+import { Cordova, IonicNativePlugin, Plugin } from '@ionic-native/core';
+
+/**
+ * @name App Center Shared
+ * @capacitorincompatible true
+ * @description
+ * Exposes additional shared APIs for App Center.
+ *
+ * For more info, please see https://docs.microsoft.com/en-us/appcenter/sdk/other-apis/cordova
+ *
+ * @usage
+ * ```typescript
+ * import { AppCenter } from '@ionic-native/app-center-shared/ngx';
+ * 
+ * ...
+ *
+ * constructor(private appCenterShared: AppCenter) { }
+ *
+ * async getInstallId() {    
+ *   const id = await this.appCenter.getInstallId();
+ * }
+ * 
+ * async setUserId() {  
+ *   try{
+ *     await this.appCenter.setUserId('i-am-john');
+ *   } catch (e){
+ *     console.log(e);
+ *   }
+ * }
+ * ```
+ */
+@Plugin({
+  pluginName: 'AppCenter',
+  plugin: 'cordova-plugin-appcenter-shared',
+  pluginRef: 'AppCenter',
+  repo: 'https://github.com/Microsoft/appcenter-sdk-cordova/tree/master/cordova-plugin-appcenter-shared',
+  platforms: ['Android', 'iOS'],
+})
+@Injectable()
+export class AppCenter extends IonicNativePlugin {
+  /**
+   * Returns AppCenter UUID.
+   * For more info, please see: https://docs.microsoft.com/en-us/appcenter/sdk/other-apis/cordova#identify-installations
+   * @returns {Promise<string>} Install ID
+   */
+  @Cordova()
+  getInstallId(): Promise<string> {
+    return;
+  }
+
+  /**
+   * Set a user ID that's used to augment crash reports.
+   * For more info, please see: https://docs.microsoft.com/en-us/appcenter/sdk/other-apis/cordova#identify-users
+   * @param {string} userId Ex. "your-user-id"
+   * @returns {Promise<void>}
+   */
+  @Cordova()
+  setUserId(userId: string): Promise<void> {
+    return;
+  }
+}