Add quote api example (#20)

In preparation for a v2 release that will support the Lambda Runtime v2, I'm adding an end-to-end example project

Examples/quoteapi/Sources/QuoteService.swift

@@ -0,0 +1,49 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift OpenAPI Lambda open source project
+//
+// Copyright (c) 2023 Amazon.com, Inc. or its affiliates
+//                    and the Swift OpenAPI Lambda project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift OpenAPI Lambda project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import Foundation
+import OpenAPIRuntime
+import OpenAPILambda
+
+@main
+struct QuoteServiceImpl: APIProtocol, OpenAPILambdaHttpApi {
+
+    init(transport: OpenAPILambdaTransport) throws {
+        try self.registerHandlers(on: transport)
+    }
+
+    func getQuote(_ input: Operations.getQuote.Input) async throws -> Operations.getQuote.Output {
+
+        let symbol = input.path.symbol
+
+        var date: Date = Date()
+        if let dateString = input.query.date {
+            let dateFormatter = DateFormatter()
+            dateFormatter.dateFormat = "yyyyMMdd"
+            date = dateFormatter.date(from: dateString) ?? Date()
+        }
+
+        let price = Components.Schemas.quote(
+            symbol: symbol,
+            price: Double.random(in: 100..<150).rounded(),
+            change: Double.random(in: -5..<5).rounded(),
+            changePercent: Double.random(in: -0.05..<0.05),
+            volume: Double.random(in: 10000..<100000).rounded(),
+            timestamp: date
+        )
+
+        return .ok(.init(body: .json(price)))
+    }
+}

Examples/quoteapi/Sources/openapi-generator-config.yaml

@@ -0,0 +1,4 @@
+generate:
+  - types
+  - server
+  

Examples/quoteapi/Sources/openapi.yaml

@@ -0,0 +1,54 @@
+openapi: 3.1.0
+info:
+  title: StockQuoteService
+  version: 1.0.0
+  
+components:
+  schemas:
+    quote:
+      type: object
+      properties:
+        symbol:
+          type: string
+        price:
+          type: number
+        change:
+          type: number
+        changePercent:
+          type: number
+        volume:
+          type: number
+        timestamp:
+          type: string
+          format: date-time
+          
+paths:
+  /stocks/{symbol}:
+    get:
+      summary: Get the latest quote for a stock
+      operationId: getQuote
+      parameters:
+        - name: symbol
+          in: path
+          required: true
+          schema:
+            type: string
+        - name: date
+          in: query
+          required: false
+          schema:
+            type: string
+            format: date
+      tags:
+        - stocks
+      responses:
+        200:
+          description: OK
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/quote'
+        400:
+          description: Bad Request
+        404:
+          description: Not Found