docs: fix broken links

[lechnerc77]

Purpose

• Fix broken links
• reformat markdown
• closes #815

Does this introduce a breaking change?

[ ] Yes
[X] No

Pull Request Type

What kind of change does this Pull Request introduce?

[ ] Bugfix
[ ] Feature
[ ] Refactoring (no functional changes, no api changes)
[X] Documentation content changes
[ ] Other... Please describe:

How to Test

• Run GH Action with periodic link checker

What to Check

Verify that the following are valid:

• GH Action executes without findings

Other Information

developers.sap.com throws 403s when checked via GH Action since weekend. Put it on ignore list

Checklist for reviewer

The following organizational tasks must be completed before merging this PR:

• [X] The PR is assigned to the Terraform project and a status is set (typically "in review").
• [X] The PR has the matching labels assigned to it.
• [X] The PR has a milestone assigned to it.
• [X] If the PR closes an issue, the issue is referenced.
• [X] Possible follow-up items are created and linked.