Mention need for config edit for root/masterpw login

[kannes]

I tried to log in to a misconfigured GeoServer as root with the masterpw and was horrified when it did not work. Only via Google I found out that one needs to explicitely enable this special login: https://docs.geoserver.org/2.24.x/en/user/security/passwd.html#keystore-password

This PR simply adds another line to the masterpw.info file so that there is a better chance for discovery. :)

Checklist

• I have read the contribution guidelines.
• I have sent a Contribution Licence Agreement (not required for small changes, e.g., fixing typos in documentation).
• First PR targets the main branch (backports managed later; ignore for branch specific issues).
• All the build checks are green (see automated QA checks).

For core and extension modules:

• New unit tests have been added covering the changes.
• Documentation has been updated (if change is visible to end users).
• The REST API docs have been updated (when changing configuration objects or the REST controllers).
• There is an issue in the GeoServer Jira (except for changes that do not affect administrators or end users in any way).
• Commit message(s) must be in the form [GEOS-XYZWV] Title of the Jira ticket.
• Bug fixes and small new features are presented as a single commit.
• Each commit has a single objective (if there are multiple commits, each has a separate JIRA ticket describing its goal).

[jodygarnett]

The user interface setting is Allow "root" user to login as Admin when editing the default Master Password Provider.

[aaime]

This PR was merged with failing QA, now the main branch is tainted and all PRs will fail QA as well.
The code formatting check failed, the code was not built with maven (see the QA documentation, linked from the checklist, which was not even compiled).

@jodygarnett there is no need to merge every single outstanding PR when doing a release, especially not one that fails some of the github actions check.

I'll close the backport and manually fix main....

[aaime]

Btw, is there a Jira ticket for this? Or think change won't show up in release notes/announcements.

[kannes]

Btw, is there a Jira ticket for this? Or think change won't show up in release notes/announcements.

Nope, all I got from atlassian.net was a loop of Sign In -> Spinning Icon -> Sign In. I'm sorry but I cannot invest time with troubleshooting yet another account on yet another proprietary website. :\