Update AAI tutorial

Some updates on the AAI tutorial.

• Removed outdated or (for the trying-to-login-via-AAI user irrelevant) information.
• More explicit information on ORCID etc login
• Reduce the role of the Events platform for this tutorial to avoid the misunderstanding that this is only about events

---

• Review here versus old version
• Edit here

_posts/2021/06/2021-06-23-how-to-helmholtz-aai.md

@@ -16,7 +16,7 @@ excerpt: >
 # Login to Helmholtz Cloud Services via Helmholtz AAI
 
 Helmholtz AAI allows seamless access to a large and growing number of Cloud Services,
-accessible via the [Helmholtz Cloud Portal](https://helmholtz.cloud/services) and
+many of them accessible via the [Helmholtz Cloud Portal](https://helmholtz.cloud/services) and
 supported by [HIFIS]({% link index.md %}).
 
 #### Exemplary Helmholtz Cloud Service: Events Management Platform