[Enhancement] mariabackup option of '--password' or '-p' without specifying password in commandline

Hi.

During mariabackup testing, I realized that for the option of "--password" I had to specify password in the commandline together.
If I use the option only without password, It says it requires a argument.

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[root@maria-master full]# mariabackup --backup --target-dir /tmp/full -uroot -p
mariabackup: option '-p' requires an argument

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For security purpose, It would be great that we just get the password input in next commandline like the other client tool does.

Great thanks,
Kwangbock