Pushing changes for Atlan backend

[Pujathacker2210]

Key changes -

• Added Atlan as a backend for Usernaut
• Implemented FetchGroups, CreateGroup and DeleteGroup functions
• Added a check in controller to create Atlan group only if rover backend is mentioned for the same group in the CR
• Group Sync and user sync is handled automatically via ldap/rover

[Copilot]

Pull Request Overview

This PR adds Atlan as a new backend for the Usernaut system, enabling group management operations while leveraging LDAP/Rover for user synchronization. The implementation includes API client setup, group operations (fetch, create, delete), and validation logic to ensure Rover groups exist before creating corresponding Atlan groups.

Key changes:

• Integration of Atlan backend with group management capabilities
• Implementation of stub user operations that delegate to LDAP/Rover
• Addition of validation logic requiring Rover backend existence for Atlan group creation

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
pkg/clients/client.go	Adds Atlan case to backend factory and moves config initialization for reuse
pkg/clients/atlan/client.go	Core Atlan client implementation with HTTP client setup and authentication
pkg/clients/atlan/teams.go	Group/team operations including fetch, create, and delete functionality
pkg/clients/atlan/users.go	Stub user operations that return empty data (handled by LDAP)
pkg/clients/atlan/team_membership.go	Stub team membership operations (handled by LDAP)
internal/controller/group_controller.go	Validation logic to ensure Rover group exists before Atlan group creation
appconfig/default.yaml	Configuration template for Atlan backend connection

[Copilot]

The team name sanitization logic only handles spaces and hyphens but may not cover all invalid characters for Atlan group names. Consider using a more comprehensive sanitization approach or regex to ensure all invalid characters are properly handled.

Suggested change

	internalName := strings.ToLower(strings.ReplaceAll(team.Name, " ", "_"))
	internalName = strings.ReplaceAll(internalName, "-", "_")
	// Use regex to sanitize the team name: lowercase, alphanumeric + underscore only
	regex := regexp.MustCompile(`[^a-z0-9_]`)
	internalName := regex.ReplaceAllString(strings.ToLower(team.Name), "_")

[vinamra28]

closing in favour of #162