cmd/clef: replace password arg with prompt

[johnsBeharry]

Feature: cmd/clef

Scenario: addpw prompts user to type password
  When a user runs "clef addpw 0x0000000000000000000000000000000000000000"
  Then the user is prompted to enter a password
  And then the user is prompted to enter the same password again to confirm

NOTES

• As specified in Clef addpw should not take password via command line  #17829 the problem is passing a password to clef addpw <account> <password> exposes the password to bash_history. The solution is to prompt the user to enter the password instead.
• This PR borrows the getPassword function from cmd/geth/accountcmd.go with some simplification for clef.

[holiman]

Oh, my bad. I forgot that the PR to have a master password is not in master yet, the idea was to reuse the same password dialog that's already in that PR (#17704) . If made on top of that one, it would be pretty simple to make it work also in non-CLI mode, with an external UI.

[johnsBeharry]

@holiman I'm closing this in favor of PR #17897 which was branched off of master containing #17704