chore: relocate amber

[Yicong-Huang]

According to the reorganization plan #3846. This PR moves core/amber out to root.

resolves #3865

[Copilot]

Pull Request Overview

This PR relocates the amber engine module from core/amber to the root directory as part of a reorganization plan. This change affects path references throughout the codebase that previously pointed to the amber module within the core directory.

• Moved amber engine from core/amber to root amber directory
• Updated all path references and imports to reflect the new location
• Relocated build and deployment scripts from core/scripts to root bin directory

Reviewed Changes

Copilot reviewed 6 out of 608 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
amber/src/main/python/core/storage/iceberg/test_iceberg_document.py	Updated directory path to reflect amber's new location
access-control-service/src/main/scala/org/apache/texera/service/AccessControlService.scala	Replaced import with direct path construction and added required import
Dockerfile	Updated script paths to point to relocated bin directory
CONTRIBUTING.md	Updated documentation paths for amber engine location
.github/workflows/github-action-build.yml	Updated CI workflow paths for relocated directories
.github/labeler.yml	Updated GitHub labeler configuration for new directory structure

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