Add PaymentMetadata and integrate it with PaymentDetail

- Introduces the `PaymentMetadata` struct with a randomly generated 16-byte ID ([u8; 16]), lighter than the 32-byte ID used in `PaymentDetail`.
- Adds a pointer from `PaymentDetail` to `PaymentMetadata`, available only for `PaymentKind::Bolt11`, `PaymentKind::Bolt12Offer` and  `PaymentKind::Bolt12Refund`  .
- For `Bolt11`, the metadata reference is an `Option<PaymentMetadataId>`.
- For `Bolt12Refund` and `Bolt12Offer`, it's a `Vec<PaymentMetadataId>`, allowing multiple metadata entries per detail.

Author: moisesPompilio

src/event.rs

@@ -745,6 +745,7 @@ where
 							offer_id,
 							payer_note,
 							quantity,
+							payment_metadata_ids: Vec::new(),
 						};
 
 						let payment = PaymentDetails::new(

src/payment/bolt11.rs

@@ -180,6 +180,7 @@ impl Bolt11Payment {
 					hash: payment_hash,
 					preimage: None,
 					secret: payment_secret,
+					payment_metadata_id: None,
 				};
 				let payment = PaymentDetails::new(
 					payment_id,
@@ -203,6 +204,7 @@ impl Bolt11Payment {
 							hash: payment_hash,
 							preimage: None,
 							secret: payment_secret,
+							payment_metadata_id: None,
 						};
 						let payment = PaymentDetails::new(
 							payment_id,
@@ -315,6 +317,7 @@ impl Bolt11Payment {
 					hash: payment_hash,
 					preimage: None,
 					secret: Some(*payment_secret),
+					payment_metadata_id: None,
 				};
 
 				let payment = PaymentDetails::new(
@@ -339,6 +342,7 @@ impl Bolt11Payment {
 							hash: payment_hash,
 							preimage: None,
 							secret: Some(*payment_secret),
+							payment_metadata_id: None,
 						};
 						let payment = PaymentDetails::new(
 							payment_id,
@@ -573,6 +577,7 @@ impl Bolt11Payment {
 			hash: payment_hash,
 			preimage,
 			secret: Some(payment_secret.clone()),
+			payment_metadata_id: None,
 		};
 		let payment = PaymentDetails::new(
 			id,

src/payment/bolt12.rs

@@ -106,6 +106,7 @@ impl Bolt12Payment {
 					offer_id: offer.id(),
 					payer_note: payer_note.map(UntrustedString),
 					quantity,
+					payment_metadata_ids: Vec::new(),
 				};
 				let payment = PaymentDetails::new(
 					payment_id,
@@ -131,6 +132,7 @@ impl Bolt12Payment {
 							offer_id: offer.id(),
 							payer_note: payer_note.map(UntrustedString),
 							quantity,
+							payment_metadata_ids: Vec::new(),
 						};
 						let payment = PaymentDetails::new(
 							payment_id,
@@ -212,6 +214,7 @@ impl Bolt12Payment {
 					offer_id: offer.id(),
 					payer_note: payer_note.map(UntrustedString),
 					quantity,
+					payment_metadata_ids: Vec::new(),
 				};
 				let payment = PaymentDetails::new(
 					payment_id,
@@ -237,6 +240,7 @@ impl Bolt12Payment {
 							offer_id: offer.id(),
 							payer_note: payer_note.map(UntrustedString),
 							quantity,
+							payment_metadata_ids: Vec::new(),
 						};
 						let payment = PaymentDetails::new(
 							payment_id,
@@ -334,6 +338,7 @@ impl Bolt12Payment {
 			secret: None,
 			payer_note: refund.payer_note().map(|note| UntrustedString(note.0.to_string())),
 			quantity: refund.quantity(),
+			payment_metadata_ids: Vec::new(),
 		};
 
 		let payment = PaymentDetails::new(
@@ -400,6 +405,7 @@ impl Bolt12Payment {
 			secret: None,
 			payer_note: payer_note.map(|note| UntrustedString(note)),
 			quantity,
+			payment_metadata_ids: Vec::new(),
 		};
 		let payment = PaymentDetails::new(
 			payment_id,