CAMEL-20888 - Remove Kotlin DSL

[apupier]

Kotlin DSL was deprecated in Camel 4.7
It was not used a lot and it takes a fair part of the build time.

Description

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[apupier]

better to merge these other Pull Requests first to avoid breaking some other projects:

• CAMEL-20888 - update link related to Kotlin camel-website#1225
• CAMEL-20888 - Remove Kotlin DSl camel-kamelets-examples#91

finally not needed, will be done later when projects will adopt Camel 4.9:

• CAMEL-20888 - Remove Kotlin DSL camel-quarkus-examples#270
• CAMEL-20888 - Remove Kotlin DSL camel-quarkus#6438
• CAMEL-20888 - Remove Kotlin DSL camel-spring-boot#1214
• CAMEL-20888 - Remove Kotlin DSL camel-k#5833

EDIT: only Camel Quarkus is required as Camel K is based on older version (only deprecation in Camel K would be nice)
@jamesnetherton will take care of the Quarkus side https://github.com/jamesnetherton

EDIT2: in fact, Camel Quarkus is still on Camel 4.7, James will take care of the upgrade when Camel Quarkus will move to Camel 4.9

[orpiske]

+1

[davsclaus]

Need to regen as main branch has updated since

[davsclaus]

@apupier the upgrade guide doc has a conflict

[apupier]

while checking camel-website if requring new changes, I found https://camel.apache.org/blog/2024/02/camel44-whatsnew/#kotlin-api

Kotlin API is not the replacement of Kotlin DSL (it is a separate module for now). While it is experimental there may be breaking changes in upcoming releases.

This PR is in fact removing all kotlin related things

[davsclaus]

while checking camel-website if requring new changes, I found https://camel.apache.org/blog/2024/02/camel44-whatsnew/#kotlin-api

Kotlin API is not the replacement of Kotlin DSL (it is a separate module for now). While it is experimental there may be breaking changes in upcoming releases.

This PR is in fact removing all kotlin related things

That is fine - all of this was experimental and manually hand code to be up to date. And there is little uptake of this.
This kind of stuff is better first done outside ASF to build up and gain momentum before dumped to core project and left for us to maintain.