refactor(core): Clean up dependencies (#645)

An upcoming kork bump will move some dependencies from api to
implementation; update places that were depending on the api
dependency to include it explicitly.

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

fiat-api/fiat-api.gradle

@@ -28,6 +28,7 @@ dependencies {
   implementation "com.netflix.spinnaker.kork:kork-web"
   implementation "com.squareup.retrofit:retrofit"
   implementation "com.squareup.retrofit:converter-jackson"
+  implementation "org.apache.commons:commons-lang3"
 
   compileOnly "javax.servlet:javax.servlet-api"