Make necessary configs available to the front end

[kamil4]

Fixes #1127

As it turns out, config variables with confidentiality set to 2 aren't actually available to the front end as part of Session::init. The server distinguishes only between public and admin; there is no separate provision for logged in users.

This patch follows this model and changes the confidentiality of three variables that should be exposed to logged in users (editor_enabled, upload_processing_limit, and public_photos_hidden) to 0.

An alternative implementation would be for Session::init to treat logged in users as a separate category. Feedback welcome...

[sonarqubecloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
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No Coverage information
78.1% Duplication

[d7415]

I haven't tested it, but it looks sensible.

I like the idea of a "logged in"/"user" confidentiality, but in the meantime I see no major issue with leaking these settings to the public scope.

[ildyria]

Ideally the logged-in users should be seeing more than the non-logged-in but less than admin level. That would be the point of having the confidentiality set to 1 instead of 2 actually.

However I am not sure the logic of Session::init() allows this differentiation.