remove .ddev directory

[gilzow]

Describe the bug

the configuration in .ddev/config.yaml is not connected to the configuration in .platform.app.yaml and therefore can drift and fall out-of-sync. Suggest removing .ddev directory and instead point users to the ddev+platformsh addon instructions.

Include some logs

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Reproducing

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Expected behavior

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Your environment

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Screenshots

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Additional context

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