[TASK] get backend working in TYPO3 v11 again (add routing)

[kaystrobach]

Description

Please describe your changes in detail according to the information below

Related Issue

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Motivation and Context

Why is this change required? What problem does it solve?

How Has This Been Tested?

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Types of changes

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• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

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• [ ] I have read the contribution guide
• [ ] I have created an issue following the issue guide
• [ ] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.

[gilzow]

This is a Typo3 v10 template, and the white list added in the PR includes a bunch of non-related file types. Closing as irrelevant.