feat: Implement GUI for SPED Automático with configuration management and theme support

- Added a new GUI application using the Iced library for user interaction.
- Implemented configuration loading from an INI file, including fields for model file, spreadsheet path, and reporting month.
- Introduced theme management with options for auto, light, and dark modes based on system preferences.
- Added functionality to browse for model and spreadsheet files.
- Implemented validation and formatting for the reporting month input.
- Integrated asynchronous processing of the SPED generation logic, with user feedback during execution.
- Created a logging mechanism to track application events and errors.
- Added tests for core functionalities including file reading/writing and data processing.

Cargo.toml

@@ -0,0 +1,32 @@
+[package]
+name = "sped_automatico"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+chardetng = "0.1"
+encoding_rs = "0.8"
+anyhow = "1.0"
+clap = { version = "4.0", features = ["derive"] }
+log = "0.4"
+env_logger = "0.9"
+ini = "1.3.0"
+calamine =  { version = "0.30.1"}
+chrono = "0.4"
+iced = { version = "0.10", features = ["tokio"] }
+rfd = "0.9"
+winreg = "0.10"
+
+[[bin]]
+name = "gui"
+path = "src/bin/gui.rs"
+windows-subsystem = "windows"
+
+[build-dependencies]
+winres = "0.1"
+
+[profile.dev]
+opt-level = 0
+
+[profile.release]
+opt-level = 3