build: update to spring boot 4.1

[c4181]

Update to Spring Boot 4.1

• Migrate to tomcat since undertow is no longer supported
• Remove the TRACE filter since Tomcat blocks it by default
• Remove the ant_pattern_matcher config since the ant matcher is deprecated
• Update deprecated methods in the Kafka AdminClient

[Copilot]

Pull request overview

Upgrades Kafdrop to Spring Boot 4.1 and migrates affected web, Jackson, Actuator, testing, and Kafka APIs.

Changes:

• Replaces Undertow with Tomcat and adds TRACK filtering.
• Migrates Spring Boot 4.1 package and configuration APIs.
• Updates Kafka consumer-group listing API.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
pom.xml	Updates Spring Boot, web server, Springdoc, and test dependencies.
src/main/java/kafdrop/Kafdrop.java	Replaces Undertow configuration with a TRACK filter.
src/main/java/kafdrop/config/HealthCheckConfiguration.java	Adapts health reporting to descriptor APIs.
src/main/java/kafdrop/config/ObjectMapperConfig.java	Migrates to Jackson 3 JsonMapper.
src/main/java/kafdrop/controller/BasicErrorController.java	Updates Spring Boot error API imports.
src/main/java/kafdrop/service/KafkaHighLevelAdminClient.java	Migrates Kafka group listing APIs.
src/main/resources/application.yml	Updates Jackson enum configuration.
src/test/java/kafdrop/KafdropTest.java	Migrates TestRestTemplate configuration.

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[c4181]

The STREAMS group type not working is actually what prompted my PR.

The call to listConsumerGroupOffsets happily accepts and returns the correct info for CLASSIC, CONSUMER, and STREAMS group types. If a SHARE group is passed in, it'll just ignore it.

There will need to be a little bit of refactoring to get share group information displayed.

[Bert-R]

I've been reading a bit more about this and tend to agree with Copilot. It seems like listConsumerGroupOffsets will throw an exception when it receives something other than a consumer group.
So, I'd say there are two options:

• Rename this method into listGroups, retain the filter behavior you just implemented (list all groups) and update callers of the renamed method to accept all types of groups.
• Retain the name and the filtering, though by calling listGroups(org.apache.kafka.clients.admin.ListGroupsOptions.forConsumerGroups()) now.

[Bert-R]

@c4181 Thanks! This contribution is highly appreciated. It was on my list of things to do since long, but I couldn't find the time.

I've asked Copilot for a review. See the review comments. Besides that, our linter complains about a line that is too long:

src/main/java/kafdrop/Kafdrop.java:
  	71: Line too long (186 instead of 120)

Can you have a look?