feat: add LNBits wallet plugin integration

- Introduced LNBits as a Lightning Network wallet provider for Lamassu ATMs.
- Added configuration options for LNBits in the environment variables.
- Implemented core functionalities including invoice creation, payment processing, balance monitoring, and payment status tracking.
- Created unit tests for the LNBits plugin to ensure functionality and error handling.
- Updated development environment setup to include LNBits configuration.

packages/server/migrations/1750000000000-add-lnbits-config.js

@@ -0,0 +1,36 @@
+const db = require('./db')
+
+exports.up = function (next) {
+  const sql = `
+    INSERT INTO user_config (name, display_name, type, data_type, config_type, enabled, secret, options)
+    VALUES 
+      ('lnbitsEndpoint', 'LNBits Server URL', 'text', 'string', 'wallets', false, false, null),
+      ('lnbitsAdminKey', 'LNBits Admin Key', 'text', 'string', 'wallets', false, true, null)
+    ON CONFLICT (name) DO NOTHING;
+    
+    -- Add LNBits as a valid wallet option for Lightning Network
+    INSERT INTO user_config (name, display_name, type, data_type, config_type, enabled, secret, options)
+    VALUES 
+      ('LN_wallet', 'Lightning Network Wallet', 'text', 'string', 'wallets', true, false, 
+       '[{"code": "lnbits", "display": "LNBits"}, {"code": "galoy", "display": "Galoy (Blink)"}, {"code": "bitcoind", "display": "Bitcoin Core"}]')
+    ON CONFLICT (name) 
+    DO UPDATE SET options = EXCLUDED.options
+    WHERE user_config.options NOT LIKE '%lnbits%';
+  `
+
+  db.multi(sql, next)
+}
+
+exports.down = function (next) {
+  const sql = `
+    DELETE FROM user_config 
+    WHERE name IN ('lnbitsEndpoint', 'lnbitsAdminKey');
+    
+    -- Remove LNBits from wallet options
+    UPDATE user_config 
+    SET options = REPLACE(options, ', {"code": "lnbits", "display": "LNBits"}', '')
+    WHERE name = 'LN_wallet';
+  `
+
+  db.multi(sql, next)
+}