Idea: Support persistence config in items builder

[jimtng]

So that we can specify how the item should be persisted in items builder too.

items.build do
  number_item Number1 do
    persist :on_change # add to the default persistence
    persist %i[on_change on_update], service: :influxdb # add to influxdb persistence
  end

  number_item Number2, persist: :on_update

  number_item Number3 do
    persist %i[on_update on_change], 
      every: 5.minutes, 
      service: influxdb, 
      filter: ->(value) { value.between?(5, 10) }
  end

  number_item Number4, persist: { cron: "* * * * * *" }
end