Add delivery options for "kn broker create"

[rhuss]

Feature request

Actually, the support for broker options is quite limited, only the broker class can be currently specified, but none of the delivery options that are described in https://github.com/knative/eventing/blob/5e3183b552cabe35ae1015fa1baff5cd67c0b7cf/pkg/apis/duck/v1/delivery_types.go#L31-L84

These options are independent of the broker implementation and can be typed (.e.g --dl-sink). This is different from #1525 where a reference to an implementation-specific configuration should be able to add.

Use case

Creating a broker with delivery options that are different from the default values.

UI Example

The following options are proposals, the detailed naming is up to discussion:

--dl-sink <sink reference>              Reference to a sink for delivering events that can not be sent
--retry <retries>.                      Number of retries before sending the event to a dead-letter sink
--timeout <duration>                    Timeout for a single request
--backoff-policy  <policy>              Backoff policy for retries, either "linear" or "exponential"
--backoff-delay <duration>              Based delay between retries
--retry-after-max <duration>            Upper bound for a duration specified in an "Retry-After" header (experimental)