Remove deprecated plugins for v1.30.0

[srebhan]

Use Case

Remove deprecated plugins that are replaced by newer ones since some time.

related to #13351

Expected behavior

Plugins should be removed. If possible a way to migrate configs containing those plugins should be provided.

Actual behavior

Plugins there.

Additional info

The following plugins are affected

• [ ] inputs.cassandra replaced by inputs.inputs.jolokia2 #13377
• [ ] inputs.httpjson replaced by inputs.http #13532
• [ ] inputs.io replaced by inputs.diskio #13536
• [ ] inputs.jolokia replaced by inputs.jolokia2 #14114
• [ ] inputs.kafka_consumer_legacy replaced by inputs.kafka_consumer #14122 Note: This plugin requires manual migration!
• [ ] inputs.snmp_legacy replaced by inputs.snmp #14123 Note: This plugin requires manual migration!
• [ ] inputs.tcp_listener replaced by inputs.socket_listener #14119
• [ ] inputs.udp_listener replaced by inputs.socket_listener #14120
• [ ] outputs.riemann_legacy replaced by outputs.riemann #14121

[powersj]

Next steps: as v1.30 will be in March 2024, then after new years 2024, circle around to this and removes these

[Hipska]

Maybe a good idea to start working with GitHub milestones again for these kind of tasks?