Add configuration for Librewolf and Zen browser with privacy-focused policies

- Created Librewolf configuration in `home/programs/librewolf/system.nix` with telemetry disabled, enhanced security settings, and enforced extensions.
- Added Zen browser configuration in `home/programs/zen/default.nix` and `home/programs/zen/system.nix`, including similar privacy policies and default search engine settings.
- Introduced `hosts/home-pc/configuration.nix` for system-wide settings, including USBGuard rules and firewall configurations.
- Established `hosts/home-pc/flake.nix` to manage NixOS modules and configurations.
- Generated `hosts/home-pc/hardware-configuration.nix` for hardware-specific settings.
- Created `hosts/home-pc/home.nix` to import various user-specific applications and settings.
- Added profile picture in `hosts/home-pc/profile_picture.jpg`.
- Implemented secrets management in `hosts/home-pc/secrets/default.nix` and `hosts/home-pc/secrets/secrets.yaml` using SOPS for encryption.
- Defined user-specific variables in `hosts/home-pc/variables.nix`, including hostname, username, and locale settings.
- Added profile picture for laptop in `hosts/laptop/profile_picture.jpg`.

hosts/laptop/variables.nix

@@ -15,7 +15,7 @@
 
     keyboardLayout = "de";
 
-    timeZone = "Europe/Paris";
+    timeZone = "Europe/Berlin";
     defaultLocale = "de_DE.UTF-8";
     extraLocale = "en_EN.UTF-8";