Migration: Help document 489581 "How do you apply software updates and security patches?"

[TibsAtWork]

The help article "How do you apply software updates and security patches?" (original URL https://help.aiven.io/en/articles/489581-how-do-you-apply-software-updates-and-security-patches) has not been migrated, and there is a demand for it.

Migrate it to the new documentation style.

[staceysalamon-aiven]

Note that most of this information already exists in the documentation. Some of the details from the conceptual parts can be added to the Maintenance window article.

Instructions on how to receive notifications are already in a how-to article in the documentation.