title: spring controller: accept date / time in many different formats
body: <p>in my controller i need to support many different date formats, like:</p>
  
  <pre><code>2018-08-24 13:00
  2018-08-24
  2009-12-31 23:59:59.999 +0100
  2019-04-08T16:01:09
  </code></pre>
  
  <p>can i just create a pojo used by controller and somehow tell spring to support multiple formats?</p>
  
  <pre><code>data class UserRequest(
          @field:DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME) // more formats?
          val start: LocalDateTime,
          // ... other fields
  )
  
  @RestController
  class MyController {
  
      @GetMapping("/api/v1/xxx")
      fun get(request: UserRequest) = ...
  }
  </code></pre>