feat(samples): refactor and simplify core samples

[rederik76]

Consolidate the existing bronze_sample, silver_sample, gold_sample, and test_data_and_orchestrator bundles into two purpose-built Databricks Asset Bundles:

• feature-samples: single-schema bundle demonstrating all framework features (CDC, snapshots, DQ, table migration, materialized views, Kafka, etc.)
• pattern-samples: multi-schema medallion bundle (bronze → silver → gold) demonstrating end-to-end integration patterns

Key changes:

• Remove test_data_and_orchestrator; fold orchestration and staging notebooks into each bundle directly
• Add per-layer schema variables (bronze_schema, silver_schema, gold_schema) to pattern-samples bundle and deploy/destroy scripts
• Add explicit database token to all targetDetails in both bundles and qualify flow-type targetTable references accordingly to align with framework's fully-qualified table name construction
• Remove DPM sample; rename pipeline resource YAMLs and job tasks for clarity
• Update dataFlowGroup values to be unique per directory to prevent cross-pipeline spec loading within a shared bundle.sourcePath
• Update all pipeline root_path values to ${workspace.file_path}/src
• Move src_notebooks to src/notebooks across both bundles
• Rewrite samples/README.md; add deploy_feature_samples.sh and deploy_pattern_samples.sh; update Sphinx documentation