Separate command line argument to force a random password

[hexmode]

Currently, there only way to avoid prompts when running canasta create is to set the password the an empty value on the command line. I prefer making this explicit by adding a -r to the options so that we leave open the possibility of someone providing an empty password in the future.

Even if the decision is made to not allow empty passwords, explicitly requesting the creation of a random password is better than the implied behavior of creating a random password when you are given a blank one. (Note that I'm not addressing the interactive dialog where the user is explicitly told a random password will be created if an empty line is provided.)

[amalpaul54111]

This looks great and works, Thank You. I guess this could be merged.
What do you think @jeffw16 ?