[FEATURE-REQUEST] annotation that identifies position instead of field name

`@SerializedName` is very useful, however, I've encountered API responses that provide data without a Field Name and in this situation `@SerializedName` is useless. To be able to process the response a custom deserializer needs to be made... which is extra work for the developer.

To make it easier on the developer, I would like to propose a new annotation - something like `@SerializedPosition(x)` where x is an integer that identifies the index of the data.

FYI: the API response I'm referring to is the first response shown at https://github.com/binance-exchange/binance-official-api-docs/blob/master/rest-api.md#market-data-endpoints