feat: Add support for masking fields in structs, slices, and maps

[n0l3r]

changes:

• Implement MaskType constants for various masking types (asterisk, censor, email, credit card, phone, zip).
• Add Masker struct and New constructor to initialize masker with options.
• Implement Mask method to apply masking to fields in a struct.
• Enhance maskRecurse method to handle nested structs, slices, arrays, and maps.
• Add masking functions for different types (maskString, maskEmail, maskCreditCard).