Track-and-trace standard (CIS6)

[DOBEN]

Task description

The standard defines the two events to enable tracking of items by external tools (e.g. block explorers).

pub struct ItemCreatedEvent {
    /// The item's id.
    pub item_id:      String,
    /// The item's metadata_url.
    pub metadata_url: Option<MetadataUrl>,
    /// Status when item was created.
    pub initial_status:      Status,
}

pub struct ItemStatusChangedEvent<A: Serial> {
    /// The item's id.
    pub item_id:         String,
    /// The item's new status.
    pub new_status:      Status,
    /// Any additional data encoded as generic bytes. Usecase-specific data can
    /// be included here such as temperature, longitude, latitude, ... .
    pub additional_data: A,
}

In preparation for the standard, the following changes were discussed:

• [x] Change itemId from a number to a String so that Universally Unique Identifier (UUID) can be used as well.
• [x] Add initial_status to the CreateEvent and display it at the front end.
• [x] Add supports (CIS0) function.