Mobile Services: Update create and delete commands

updates the create command to not prompt for password twice when using
an existing db
update the delete command logic to only delete the app if the mobile
service is deleted first
address some usability/code cleanup as well
Remove unneeded usage blocks, fix password length check to match portal
Revert "Remove unneeded usage blocks, fix password length check to match portal"

This reverts commit 9b110ba3f111cbe684856d11316ce60a40536166.
Remove usage block, fix password length check to match portal
Remove usage from delete command as well
Merge pull request #844 from phvannor/create-mobile-service-with-existing-db-only-prompt-once-for-pwd

Mobile Services: Update create and delete commands