FEDX-973 Remove Workiva Build files

[robbecker-wf]

Summary

Removes the Dockerfile and skynet.yaml files .... internal files that are not needed since CI is handled by Github Actions

Testing

• CI passes

[aviary3-wk]

Security Insights

No security relevant content was detected by automated scans.

Action Items

• Review PR for security impact; comment "security review required" if needed or unsure
• Verify aviary.yaml coverage of security relevant code

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[robbecker-wf]

once https://github.com/Workiva/frontend-web-service/pull/975 is deployed everywhere and stable we can complete this PR