Add relevant_text fields to Beacons struct with validation

[njausteve]

Type of Change

• New feature

Description

This PR introduces the following changes:

• Adds new fields minor, proximity_UUID (required), and relevant_text (optional) to the ExPass.Structs.Beacons module.
• Updates validation logic to ensure minor is a 16-bit unsigned integer and proximity_UUID is a valid UUID.
• Updates JSON encoding for the new fields, ensuring camel-cased field names are used.
• Updates and adds new tests to cover the validation and struct creation process.

Testing

• Unit tests have been added to ensure proper validation and encoding of the minor, proximity_UUID, and relevant_text fields.
• Edge cases such as invalid UUID strings, negative integers, and exceeding integer limits are covered.
• JSON encoding tests ensure correct camel-casing and handling of optional fields when they are nil.

Impact

• These changes enhance the flexibility and safety of creating Beacons structs. By introducing the proximity_UUID field, beacon uniqueness is now enforced, allowing for better tracking and validation.
• The validation logic in the ExPass.Utils.Validators module has been expanded to support field-specific error messages, improving debugging and error reporting.

Additional Information

No new dependencies were introduced. The changes remain backward-compatible with existing structures and should not affect existing behavior unless the newly added fields are used.

Checklist

• My code adheres to the coding and style guidelines of the project.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.