Adjust Spring Zeebe SDK docs

[nicpuppa]

Description

• Updated configuration properties
• Added @ZeebeSpringTest references
• Improved docs, removed reference to old configuration (with .properties file) in favor of yaml file
• Removed links to Spring Zeebe community project

closes: #3748

When should this change go live?

• [ ] This is a bug fix, security concern, or something that needs urgent release support.
• [ ] This is already available but undocumented and should be released within a week.
• [ ] This on a specific schedule and the assignee will coordinate a release with the DevEx team. (apply hold label or convert to draft PR)
• [ ] There is no urgency with this change and can be released at any time.

PR Checklist

• [ ] My changes are for an already released minor and are in /versioned_docs directory.
• [x] My changes are for the next minor and are in /docs directory (aka /next/).

• [x] My changes require an Engineering review, and I've assigned the Engineerring DRI or delegate.
• [ ] My changes require a technical writer review, and I've assigned @christinaausley as a reviewer.

[github-actions[bot]]

:wave: :robot: :thinking: Hello! Did you make your changes in all the right places?

These files were changed only in docs/. You might want to duplicate these changes in versioned_docs/version-8.5/.

• docs/apis-tools/spring-zeebe-sdk/configuration.md
• docs/apis-tools/spring-zeebe-sdk/getting-started.md
• docs/components/best-practices/architecture/deciding-about-your-stack.md
• docs/components/best-practices/development/connecting-the-workflow-engine-with-your-world.md
• docs/components/best-practices/development/testing-process-definitions.md
• docs/guides/migrating-from-camunda-7/adjusting-source-code.md
• docs/guides/migrating-from-camunda-7/conceptual-differences.md

You may have done this intentionally, but we wanted to point it out in case you didn't. You can read more about the versioning within our docs in our documentation guidelines.

[christinaausley]

@nicpuppa It looks like https://github.com/camunda/camunda-docs/issues/3748 is in review -- let me know when you would like a final review here, and if you have any particular deadline 👍

[nicpuppa]

@nicpuppa It looks like #3748 is in review -- let me know when you would like a final review here, and if you have any particular deadline 👍

Thanks @christinaausley I will let you know when the PR is ready 👍