init: Evaluate sysperms before config file #26512

Fixes #13371

Currently we check the config file before applying the effect of the -sysperms program option. On first boot with no datadirectory this can result in directories (and settings.json file) being created with incorrect permissions.

As I mention in #13371 this will change default file permissions from what they are currently which might risk breaking changes to upstream projects. If this is not desirable, then the alternative would be to leave the current behaviour and perhaps update the docs slightly.

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Conflicts

Reviewers, this pull request conflicts with the following ones:

• #17127 (util: Set safe permissions for data directory and wallets/ subdir by hebasto)

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Thank you DrahtBot for linking #17127, I will close this for that one

This is still needed to fix versions prior to whenever #17127 might get merged. Please reopen.

But it has a bug: you can't set sysperms in the config file anymore.