BE: Auth: Support LDAP nested groups

[RomainDubois]

• Breaking change? (if so, please describe the impact and migration path for existing application instances)

What changes did you make? (Give an overview)
Closes #390
I changed the way the LDAP groups of the user are collected. Instead of direct request to LDAP, I rely on the Spring LDAP class which has been designed to handle nested groups.

Is there anything you'd like reviewers to focus on?
No

How Has This Been Tested? (put an "x" (case-sensitive!) next to an item)

• No need to
• Manually (cf. issue Auth: Support LDAP nested groups #390 )
• Unit checks
• Integration checks
• Covered by existing automation

Checklist (put an "x" (case-sensitive!) next to all the items, otherwise the build will fail)

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (e.g. ENVIRONMENT VARIABLES)
• My changes generate no new warnings (e.g. Sonar is happy)
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged

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[github-actions]

Hi RomainDubois! 👋

Welcome, and thank you for opening your first PR in the repo!

Please wait for triaging by our maintainers.

Please take a look at our contributing guide.

[Haarolean]

@RomainDubois does replacing the super class impact the existing setups in any way?

[RomainDubois]

@RomainDubois does replacing the super class impact the existing setups in any way?

No, it inherits from the previous parent class and only overrides the method to fetch groups.
Source here : https://github.com/spring-projects/spring-security/blob/main/ldap/src/main/java/org/springframework/security/ldap/userdetails/NestedLdapAuthoritiesPopulator.java

[Haarolean]

@RomainDubois thanks for your first contribution to kafbat ui!