RFR: 7820: Add validations for master password [v4]

[Marcus Hirt]

On Thu, 28 Jul 2022 00:59:54 GMT, Suchita Chaturvedi <schaturvedi at openjdk.org> wrote:

>> This PR adds password validations for master password field.
>
> Suchita Chaturvedi has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Minor modifications as per review

Marked as reviewed by hirt (Lead).

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PR: https://git.openjdk.org/jmc/pull/406