Convert yet more configuration options to YAML

With a particular focus on custom logic and caching.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=146258446

docs/configuration.md

@@ -78,6 +78,9 @@ description of each option:
 ```yaml
 appEngine:
   projectId: # Your App Engine project ID
+  toolsServiceUrl:
+    hostName: tools-dot-PROJECT-ID.appspot.com  # Insert your project ID
+    port: 443
 
 gSuite:
   domainName: # Your G Suite domain name