Expose the 'sanitize' system for backup restores to the web GUI

[uberbrady]

We built the 'sanitize' system for doing backup restores, but really only exposed it in the CLI. We've even gone through some passes to improve it, somewhat, and so it's getting better. It's probably time to start exposing it in the UI.

Because we are changing a battle-tested system and adding some highly experimental features to it, I thought the checkbox for whether you're using it should default to 'off' - but there's a new .env-var that you can set to make the default be 'on'.

Additionally, while I was going through the Javascript code that handles the 'restore' and 'delete' buttons, I simplified it a bit, making it shorter and more readable.

I'm marking this as draft because there are still some other fixes I want to sneak in there before it's ready. Namely, I need to fully test a backup that has prefixes, and I need to figure out why a local backup I have on my machine only runs with 'clean' mode turned off.

But I thought at least getting this up would give @snipe a chance to see how it looks and make suggestions on UI changes.

[what-the-diff]

PR Summary

• Enhanced Security Configuration Through Environment Variables
  Introduced an option (SANITIZE_BY_DEFAULT=false) in the sample environment configuration file. This allows for easier customization of your app's security settings.

• Improvements to Settings Controller
  The postRestore function in the SettingsController now accepts a Request object, providing it with more information about the client request. It also optionally sanitizes data (cleans sensitive information) before restoring from backups, based on a new input parameter.

• Expansion of Backup Configuration Options
  We've included a new sanitize_by_default option in the backup configuration. With this, the system can be configured to automatically sanitize backups.

• Performance and Security Upgrades to snipeit.js
  Made the web app more efficient by removing redundant variables and consolidating event handling. Before an action as critical as restore, it now factors in whether the app is locked or not, adding another layer of security.

• Wider Language Support for Backup Procedures
  Added additional language support by including translations for new backup related strings, making backup instructions clearer for non-English speakers.

• User Interface Enhancements for Backup/Restore
  Introduced a new interactive dialogue to confirm restore actions. Users can now choose to clean the backup before restoration straight from the interface. Also, streamlined event handling for buttons in the backup settings page for improved user interaction.

Note: This summary might not cover all minor changes made. Please ensure to review the actual code changes for complete accuracy.