feat: update spring-boot to 3.x

[LukasLohoff]

🚨 BREAKING CHANGE 🚨

Description

Updates spring boot to 3.1.x / spring to 6.1 and also updates related dependencies:

• spring 5.x -> 6.1
• hibernate 5.x -> 6.2.7
• hibernate-types-52 -> hypersistence-utils-hibernate-62 (see https://github.com/vladmihalcea/hypersistence-utils#migrating-to-version-3)
• springdoc-openapi 1.6.14 -> 2.2.0
• keycloak-admin-client 19.0.3 -> 22.0.1
• git-commit-id-plugin -> 6.0.0
• Apache HttpClient in HttpUtil (4 -> 5)
• minor improvements / cleanup

@terrestris/devs Please review

Migration Guide

• update java EE 8 dependencies to jakarta EE 9 (see https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-3.0-Migration-Guide#jakarta-ee)
• update your application.properties or application.yml according to the changes made in this Pull Request
• update repositories
  • update @QueryHints annotations
  • e.g. org.hibernate.annotations.QueryHints.CACHEABLE -> AvailableHints.HINT_CACHEABLE
  • if you use custom data fetching methods, migration steps for hibernate 6 / 6.1 / 6.2 might be necessary
    • especially consider https://github.com/hibernate/hibernate-orm/blob/6.0/migration-guide.adoc#removals
    • for more information see the hibernate migration guides listed below
• update your SecurityConfigs which extends KeycloakWebSecurityConfig or SimpleWebSecurityConfig
  • update your filter chain according to the the spring security migration guides below
  • replace antMatchers with requestMatchers, ignoringAntMatchers with ignoringRequestMatchers
  • if required, explicitly add .anyRequest().authenticated() to the end of your filter chain, as this is no longer the default
  • update your rules for swagger (/v3/api-docs) if they're not already updated
• update your git-commit-id-plugin configuration and check if the version set in shogun is overridden (for more information see Fix build time for docker images #730)

Useful resources

• https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-3.0-Migration-Guide
• https://docs.spring.io/spring-security/reference/migration/index.html
• https://docs.spring.io/spring-security/reference/5.8/migration/index.html
• https://springdoc.org/v2/
• https://github.com/hibernate/hibernate-orm/blob/6.0/migration-guide.adoc
• https://github.com/hibernate/hibernate-orm/blob/6.1/migration-guide.adoc
• https://github.com/hibernate/hibernate-orm/blob/6.2/migration-guide.adoc
• https://thorben-janssen.com/migrating-to-hibernate-6/

Todos:

• migration guide
• fix circular spring references
• check why / if we need hibernate dependencies
• jakarta-mail.version is not found
• check if replacement for SpringPhysicalNamingStrategy is needed
• fix tests

Related issues or pull requests

Pull request type

• Bugfix
• Feature
• Dependency updates
• Tests
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe)

Do you introduce a breaking change?

• Yes
• No

Checklist

• I understand and agree that the changes in this PR will be licensed under the
  Apache Licence Version 2.0.
• I have followed the guidelines for contributing.
• The proposed change fits to the content of the code of conduct.
• I have added or updated tests and documentation, and the test suite passes (run mvn test locally).
• I have added a screenshot/screencast to illustrate the visual output of my update.

[dnlkoch]

Awesome @LukasLohoff!

[ahennr]

Nice work @LukasLohoff