Fix password entry usability (bsc#1226437)

[nadvornik]

What does this PR change?

• print a new line to indicate that a password was entered
• print new lines consistently during password validation
• fix a bug when valid password followed by too short confirmation got through the validation

Test coverage

• No tests: add explanation

• No tests: already covered

• Unit tests were added

• [ ] DONE

Links

Issue(s): https://github.com/SUSE/spacewalk/issues/24640 https://bugzilla.suse.com/show_bug.cgi?id=1226437

• [ ] DONE

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[admd]

@nadvornik @rjmateus how hard it would be force a password policy here ? I don't mean just the length but something like

1. password must contain one special character
2. Must contain a lower-case alphabetic
3. Must contain an upper case alphabetic
4. Must contain a digit

[nadvornik]

The entered password already is checked for spaces and tabs with regexp, extending the regexp is easy. This is however not applied on the passwords entered via commandline options.

[rjmateus]

I think that according to latest guidances don't bring security improvements. What would improve is to have a higher minimal length on the password.