feature/outlook shared mailbox (#1323)

* ⚡ Add shared mailbox support

* 🐛 Add filter field to folderMessage:getAll

* ⚡ Small changes to descriptions (#1322)

Co-authored-by: Mika Luhta <12100880+mluhta@users.noreply.github.com>

packages/nodes-base/nodes/Microsoft/Outlook/GenericFunctions.ts

@@ -14,6 +14,14 @@ import {
 } from 'n8n-workflow';
 
 export async function microsoftApiRequest(this: IExecuteFunctions | IExecuteSingleFunctions | ILoadOptionsFunctions, method: string, resource: string, body: any = {}, qs: IDataObject = {}, uri?: string, headers: IDataObject = {}, option: IDataObject = { json: true }): Promise<any> { // tslint:disable-line:no-any
+	const credentials = this.getCredentials('microsoftOutlookOAuth2Api');
+
+	let apiUrl = `https://graph.microsoft.com/v1.0/me${resource}`;
+	// If accessing shared mailbox
+	if (credentials!.useShared && credentials!.userPrincipalName) {
+		apiUrl = `https://graph.microsoft.com/v1.0/users/${credentials!.userPrincipalName}${resource}`;
+	}
+
 	const options: OptionsWithUri = {
 		headers: {
 			'Content-Type': 'application/json',
@@ -21,7 +29,7 @@ export async function microsoftApiRequest(this: IExecuteFunctions | IExecuteSing
 		method,
 		body,
 		qs,
-		uri: uri || `https://graph.microsoft.com/v1.0/me${resource}`,
+		uri: uri || apiUrl,
 	};
 	try {
 		Object.assign(options, option);