feat: add templates for transactional emails (#103)

* add template migration & router

* template CRUD

* templated transactional emails API

* zod schema fix & rearranging template columns

apps/web/prisma/schema.prisma

@@ -101,6 +101,7 @@ model Team {
   emails           Email[]
   contactBooks     ContactBook[]
   campaigns        Campaign[]
+  templates        Template[]
   dailyEmailUsages DailyEmailUsage[]
 }
 
@@ -286,6 +287,20 @@ model Campaign {
   @@index([createdAt(sort: Desc)])
 }
 
+model Template {
+  id            String         @id @default(cuid())
+  name          String
+  teamId        Int
+  subject       String
+  html          String?
+  content       String?
+  createdAt     DateTime       @default(now())
+  updatedAt     DateTime       @updatedAt
+
+  team Team @relation(fields: [teamId], references: [id], onDelete: Cascade)
+  @@index([createdAt(sort: Desc)])
+}
+
 enum EmailUsageType {
   TRANSACTIONAL
   MARKETING