refactor: better project structure (#35)

This project is starting to grow, and I've seen flaws in the initial
project structure design
I think I'll restructure the entire project directory for better
scalability and also cleaner

internal/config/paths.go

@@ -0,0 +1,42 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+)
+
+func ConfigPath() (string, error) {
+	dir, err := os.UserConfigDir()
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(dir, "iris", "config.toml"), nil
+}
+
+func StatePath() (string, error) {
+	dataHome := os.Getenv("XDG_DATA_HOME")
+	if dataHome == "" {
+		home, err := os.UserHomeDir()
+		if err != nil {
+			return "", err
+		}
+		dataHome = filepath.Join(home, ".local", "share")
+	}
+	return filepath.Join(dataHome, "iris", "state.toml"), nil
+}
+
+func CachePath() (string, error) {
+	dir, err := os.UserCacheDir()
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(dir, "iris"), nil
+}
+
+func CrashDir() (string, error) {
+	cache, err := CachePath()
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(cache, "crashes"), nil
+}