refactor: Improve config examples formatting and documentation; default Postgres container tag changed to 17-0.5.3

Improve config examples formatting and documentation

Summary

Comprehensive improvement of all 5 Database Lab Engine configuration examples with streamlined documentation, consistent formatting, and updated dependencies.

Key Changes

• Formatting: Replace tabs with spaces, remove verbose comments
• Documentation: Add concise inline comments and configuration reference links
• Platform Integration: Enhanced ASCII box design with feature highlights
• Dependencies: Update PostgreSQL container to 17-0.5.3
• Consistency: Add maintenance_work_mem, fix tool ordering, standardize terminology

Files Updated

• config.example.physical_generic.yml (golden copy)
• config.example.physical_walg.yml (WAL-G specific)
• config.example.physical_pgbackrest.yml (pgBackRest specific)
• config.example.logical_generic.yml (logical mode)
• config.example.logical_rds_iam.yml (RDS IAM specific)

Impact

• ~40% reduction in comment verbosity while maintaining clarity
• Improved readability with practical examples and better structure
• Enhanced user experience with actionable documentation
• Complete consistency across all configuration examples

Before/After Example

• Before (verbose):

  # IP addresses that can be used to access clones.
  # By default, using a loop-back to accept only local connections.
  # The empty string means "all available addresses".
  # The option supports multiple IPs (using comma-separated format) and IPv6 addresses (for example, [::1])
  cloneAccessAddresses: "127.0.0.1"

• After (concise):

  cloneAccessAddresses: "127.0.0.1" # IP addresses that can be used to access clones; supports multiple IPs and IPv6; default: "127.0.0.1" (loop-back)