Engine abstraction remove obsolete code

[pihme]

Description

Removes code that is no longer needed. Started out with a class, and then I found more.

Related issues

related to #9727

Definition of Done

Code changes:

• The changes are backwards compatibility with previous versions
• If it fixes a bug then PRs are created to backport the fix to the last two minor versions. You can trigger a backport by assigning labels (e.g. backport stable/1.3) to the PR, in case that fails you need to create backports manually.

Testing:

• There are unit/integration tests that verify all acceptance criterias of the issue
• New tests are written to ensure backwards compatibility with further versions
• The behavior is tested manually
• The change has been verified by a QA run
• The impact of the changes is verified by a benchmark

Documentation:

• The documentation is updated (e.g. BPMN reference, configuration, examples, get-started guides, etc.)
• New content is added to the release announcement
• If the PR changes how BPMN processes are validated (e.g. support new BPMN element) then the Camunda modeling team should be informed to adjust the BPMN linting.

Please refer to our review guidelines.

[github-actions]

Test Results

   812 files  +  1     812 suites  +1   1h 58m 6s ⏱️ + 19m 58s
6 047 tests  - 36  6 035 ✔️  - 38  10 💤 ±0  2 ❌ +2 
6 235 runs   - 36  6 223 ✔️  - 38  10 💤 ±0  2 ❌ +2 

For more details on these failures, see this check.

Results for commit b85075c. ± Comparison against base commit 77f9f1d.

[Zelldon]

Thanks Peter 🏕️ 🧹 👍

[pihme]

bors merge

[zeebe-bors-camunda]

Build succeeded:

• Test summary
• Java checks
• Go linting