Add CAEM-backed experiment result query classes with legacy CubeJS fallback switch

Description

Add new experiment goal result query implementations in dotCMS core that call the CAEM analytics API endpoints (introduced in issues #37223 and #37224) instead of CubeJS. The existing CubeJS-based classes are not removed — both sets coexist and a switch mechanism controls which implementation is active, allowing legacy infrastructure to remain supported during the transition.

New implementations (alongside existing CubeJS classes):

• HTTP client to communicate with the CAEM analytics API
• Bounce rate result query using the new sessions endpoint
• Exit rate result query using the new sessions endpoint with reference page
• Reach-target result query using the new sessions behavior endpoint
• URL-parameter result query using the new sessions behavior endpoint

Switch mechanism:

• A configuration switch selects between the legacy CubeJS path and the new CAEM analytics path at runtime
• No behavioral change occurs unless the switch is explicitly enabled
• The two paths query different analytics infrastructure (CubeJS vs. CAEM/ClickHouse), but should produce the same goal rates when both backends have ingested the same underlying events

Acceptance Criteria

• A new HTTP client is available to call CAEM analytics API endpoints for sessions and session behavior
• New bounce rate result query returns correct goal rates using the CAEM sessions endpoint
• New exit rate result query returns correct goal rates using the CAEM sessions endpoint with reference page
• New reach-target result query returns correct goal rates using the CAEM sessions behavior endpoint
• New URL-parameter result query returns correct goal rates using the CAEM sessions behavior endpoint
• Existing CubeJS-based result query classes remain unchanged and functional
• A switch (e.g. configuration flag) selects between the legacy CubeJS path and the new CAEM analytics path
• When the switch is disabled, the system uses the existing CubeJS implementation (no regression)
• When the switch is enabled, the system uses the new CAEM-backed implementations
• Unit tests cover each new result query class
• Unit tests cover the switch dispatch logic

Additional Context

Depends on CAEM endpoints introduced in:

• #37223 — Extend GET /v1/analytics/sessions
• #37224 — Add GET /v1/analytics/sessions/behavior