Migrate legal service from AppEngine to CloudRUN (GONRG-989)

• Update .gitlab-ci.yml with 'OSDU_GCP' variables for legal.
• Include updated osdu-gcp-cloudrun.yml pipeline

provider/legal-gcp/cloudbuild/Dockerfile.cloudbuild

+# Use the official AdoptOpenJDK for a base image.
+# https://hub.docker.com/_/openjdk
+FROM openjdk:8-slim
+WORKDIR /app
+ARG PROVIDER_NAME
+ENV PROVIDER_NAME $PROVIDER_NAME
+ARG PORT
+ENV PORT $PORT
+# Copy the jar to the production image from the builder stage.
+COPY provider/legal-${PROVIDER_NAME}/target/legal-${PROVIDER_NAME}-*-spring-boot.jar legal-${PROVIDER_NAME}.jar
+# Run the web service on container startup.
+CMD java -Djava.security.egd=file:/dev/./urandom -Dserver.port=${PORT} -jar /app/legal-${PROVIDER_NAME}.jar