Fix missing setup instructions

config/application/secret.properties.sample

+## Required for authenticated requests to profile API
+oauth2.client-id=$GIT_ECA_OAUTH_CLIENT_ID
+oauth2.client-secret=$GIT_ECA_OAUTH_CLIENT_CREDENTIALS
+
+quarkus.datasource.username=$GIT_ECA_MARIADB_USER
+quarkus.datasource.password=$GIT_ECA_MARIADB_PASSWORD
+quarkus.datasource.jdbc.url=jdbc:mariadb://$GIT_ECA_MARIADB_HOST:$GIT_ECA_MARIADB_PORT/git-eca
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