A kamelet should define which headers are supported as input and output

[davsclaus]

We should start to markup/specify which headers a sink and source kamelet can support as input and output.
For example the ftp sink kamelet should specify that the kamelet outputs ce-file as the filename of the FTP file.

The underlying FTP component also provides a set of headers
https://camel.apache.org/components/next/ftp-component.html#_message_headers

From Camel 3.17 then every component now list those in their documentation and metadata json file.

We need to consider whether we want Kamelets to expose these headers too, or we make a rule into kamelets that they output headers that the kamelet has declared.

And we also need to add into the kamelet spec how headers should be declared (ala options today).

[davsclaus]

@lburgazzoli @oscerd another requirement for kamelets

[oscerd]

We could leverage the Camel catalog from 3.17 ahead, but I guess we'll need to change the Kamelet structure to add some new fields. @lburgazzoli