refactor: storage query segregation for coretime, paras and blocks endpoints

[decrypto21]

This PR refactors storage query logic across coretime, blocks, and paras handlers to reduce code duplication by extracting common query functions into the dedicated runtime_queries/ module.

Changes Made

• Extended runtime_queries/ module with 4 new specialized query submodules:
  • coretime_assignment_provider - Relay chain CoretimeAssignmentProvider pallet queries
  • parachain_info - ParachainInfo pallet queries
  • paras - Paras pallet lifecycle queries
  • session - Session pallet queries (validators, current index)
• Extended broker module with additional functions for regions, renewals, and workload queries
• Eliminates duplicate storage query patterns across coretime, blocks, and paras handlers
• Provides reusable functions for Broker, Session, Paras, ParachainInfo, and CoretimeAssignmentProvider pallets

Implementation Details

• Extracted shared storage query logic that was duplicated across 10+ handler files
• Pattern simplification: complex inline queries → single function calls
• All coretime, blocks, and paras handlers now use runtime_queries::* for storage access
• Scope: This PR focuses on coretime/, blocks/, and paras/ endpoints only
• Follows convention established in, and closes Improve codebase segregation and reusability for storage queries #207

Code Stats
Net: cleaner, more maintainable code with centralized storage queries

[filvecchiato]

Overall pretty good, some comments to doublecheck some changes