(fix): do not expose haproxy password to UI

[oleksandr-nc]

1. Since we need a password of at least 12 characters, we use dummySecret123 instead of dummySecret
2. checkDaemonConnection expects to get the full Deploy Daemon configuration from the UI, so we get the password from the database if we get dummySecret123 from the UI and the haproxy password is present in the database.
3. I added comments everywhere in the code

[kyteinsky]

🚀

[oleksandr-nc]

/backport to stable30

[oleksandr-nc]

/backport to stable29

[backportbot]

The backport to stable30 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable30
git pull origin stable30

# Create the new backport branch
git checkout -b backport/447/stable30

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick 6d2300ae 56eab3b3

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/447/stable30

Error: No changes found in backport branch

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Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.