Setup Parent-Child Place Structure

[alexphiev]

Description:
Create database schema and relationships to support parent-child place hierarchy (e.g., National Park → specific viewpoints/waterfalls within it).

Tasks:

• Design PostgreSQL schema with parent_id foreign key
• Add place_type field (park, waterfall, peak, etc.)
• Create indexes for efficient parent-child queries
• Write auto asignment to parent method to be used during createPlace method

Acceptance Criteria:

• Can store places with optional parent reference
• Can query all children of a given parent place
• Map search returns only parent places initially