feat: add custom SMS screen

feat: custom messages database migration
feat: populate custom SMS screen with database data
feat: custom SMS creation modal
fix: small fixes on styling

migrations/1627518944902-custom-sms.js

@@ -0,0 +1,20 @@
+var db = require('./db')
+
+exports.up = function (next) {
+  var sql = [
+    `CREATE TYPE custom_message_event AS ENUM('sms_code', 'cash_out_dispense_ready')`,
+    `CREATE TABLE custom_messages (
+      id UUID PRIMARY KEY,
+      event custom_message_event NOT NULL,
+      device_id TEXT REFERENCES devices(device_id),
+      message TEXT NOT NULL
+    )`,
+    `CREATE UNIQUE INDEX uq_custom_message_per_device ON custom_messages (event, device_id)`
+  ]
+
+  db.multi(sql, next)
+}
+
+exports.down = function (next) {
+  next()
+}