Display all rules before/after submitting

[jonasraoni]

I was trying to fill in a simple password and it was difficult to pass through without knowing all the rules beforehand (I had to submit and try again until it passed).

So I see two options that might be combined here:

• Validate the rules at the frontend before submitting (or list the required rules using the password label)
• Validate all rules instead of failing on the first one, so the error message will be more helpful (a number + upper case letter + ... required)

[jonasraoni]

I was going to fix this, but it's a bug in the pkp-lib, I've opened an issue instead of adopting an alternative fix (join all errors into a single addError).