the docker image built from the master can not work correctly.

the docker image built from the master can not work correctly.

1, when run with command
`docker run -d --name manager -p 9527:9527 -p 7750:7750 apachepulsar/pulsar-manager:latest`
docker container can not start, show errors: `Error: format string...`
After add `SPRING_CONFIGURATION_FILE` and `URL` environment, container can run.

here we should add a default value for 'SPRING_CONFIGURATION_FILE' and `URL`.

2, can not login using `pulsar/pulsar` account.
there is a sentence in `application.properties`:
`If user.management.enable is true, the following account and password will no longer be valid.`

here we should set `user.management.enable` default value `false` for beginner.