[TASK] Step by step migration guide for 8.8

[hisImminence]

Related to

Epic: https://github.com/camunda/team-distribution/issues/411

Docs PR: camunda/camunda-docs#5023 (comment)

Overview

To make sure the 8.8 upgrade is as smooth as possible for customers, we should consider main setups and provide customers with a step by step guide on how to upgrade. This should be thought of E2E and integrate with the already existing docs pr.

Actions

Sub-tasks

• breakdown and define the ticket

[hisImminence]

Guide is published.