RANGER-4920: kms docker - Fix kms service url, volume support for configs

[fateh288]

What changes were proposed in this pull request?

1. Fixed service url for kms as key create operation was not succeeding
2. Introduced volume support for kms docker images so that image re-create is not required for change in configs

How was this patch tested?

1. Rebuild docker image with new kms bits, created kms docker container
2. Made some changes to kms-logback.xml (location dev-support/ranger-docker/config/ranger-kms/kms-logback.xml)
3. Restart kms docker container
4. updated kms-logback.xml correctly used now for logging (image re-create not required)