Remove duplicate code of conduct from doc (#411)

mkdocs.yml

@@ -77,12 +77,10 @@ nav:
         - 'FE Developer Guide': 'frontend/docs/developer_guide.md'
         - 'FE Installation Guide': 'frontend/docs/installation.md'
         - 'Recommended Practices': 'frontend/docs/recommended_practices.md'
-        - 'Code Of Conduct': 'frontend/CODE_OF_CONDUCT.md'
     - 'Search':
       - 'Overview': 'search/README.md'
       - 'Proxy':
         - 'Atlas Backend': 'search/docs/atlas-search.md'
-      - 'Code Of Conduct': 'search/CODE_OF_CONDUCT.md'
     - 'Metadata':
       - 'Overview': 'metadata/README.md'
       - 'Configuration':
@@ -94,13 +92,10 @@ nav:
             - 'Popular Table': 'metadata/docs/proxy/atlas/popular_tables.md'
         - 'Gremlin Backend': 'metadata/docs/proxy/gremlin.md'
         - 'Neptune Backend': 'metadata/docs/proxy/neptune.md'
-      - 'Code Of Conduct': 'metadata/CODE_OF_CONDUCT.md'
     - 'Databuilder':
       - 'Overview': 'databuilder/README.md'
       - 'Models': 'databuilder/docs/models.md'
-      - 'Code Of Conduct': 'databuilder/CODE_OF_CONDUCT.md'
     - 'Common':
       - 'Overview': 'common/README.md'
-      - 'Code Of Conduct': 'common/CODE_OF_CONDUCT.md'
   - 'FAQ': faq.md
   - 'Roadmap': roadmap.md