ParameterShovelValue.deleteafter doesn't work with integers

[inikulshin]

Probably, deleteafter JsonProperty should have special JsonConverter, writing it as integer if value can be converted to integer, and as a string otherwise.

[inikulshin]

Also, delete-after property seems to be deprecated in some RabbitMQ version, and src-delete-after should be used instead.

[micdenny]

@inikulshin if you found the error in the source code, a PR will be much appreciated, thank you 😄

[luigiberrettini]

Reference: https://www.rabbitmq.com/shovel-dynamic.html

[inikulshin]

@Pliner what's the best type for SrcDeleteAfter (every solution will require custom JsonConverter):

1. record DeleteAfter(DeleteAfterEnum, int?)
   1. SrcDeleteAfter = new DeleteAfter(DeleteAfterEnum.Never)
   2. SrcDeleteAfter = new DeleteAfter(DeleteAfterEnum.QueueLength)
   3. SrcDeleteAfter = new DeleteAfter(10)
2. string (custom JsonConverter will read/write integer if can be parsed from string)
   1. SrcDeleteAfter = DeleteAfterNever // readonly string DeleteAfterNever = "never"
   2. SrcDeleteAfter = DeleteAfterQueueLength // readonly string DeleteAfterNever = "queue-length"
   3. SrcDeleteAfter = "10"
3. enum DeleteAfter { Never = -1, QueueLength = -2 } and every other value is treated as integer
   1. SrcDeleteAfter = DeleteAfter.Never
   2. SrcDeleteAfter = DeleteAfter.QueueLength
   3. SrcDeleteAfter = (DeleteAfter)10

[inikulshin]

@zidad see previous comment.