chore: gateway image name

[njbrake]

Description

Use the name any-llm/gateway instead of any-llm-gateway to have clearer indication of the gateway being a part of the any-llm project

PR Type

🚦 Infrastructure ## Relevant issues

Checklist

• I have added unit tests that prove my fix/feature works
• New and existing tests pass locally
• Documentation was updated where necessary
• I have read and followed the contribution guidelines```

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
see 43 files with indirect coverage changes

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