NEM-388 Implement sampling scope feature

[Mateus-Cordeiro]

This PR adds a sampling scope configuration to control which tables are eligible for row sampling during database introspection.

Changes

• Added sampling yaml configuration
• Introduced SamplingScope models
  • include rules (allowlist)
  • exclude rules (denylist)
  • except_schemas and except_tables for exclude-rule exceptions (e.g exclude all tables in a schema except one)
• Implemented SamplingScopeMatcher to apply scope rules
• Integrated sampling filtering into the base_introspector before obtaining the samples

Configuration details

sampling supports:

• enabled master switch (default: true)
• Glob matching:
  • *, ?, [seq], [!seq]
• Rule behaviour detailed in sampling-scope.md file

Notes

This PR does not introduce a possibility to exclude specific columns from sampling.