Implement subscription trial optimization with conversion tracking

[Smartdevs17]

Context

Trial conversion needs optimization.

Current Limitation

Trial optimization is basic.

Expected Outcome

• Trial optimization tools
• Conversion tracking
• Trial analytics
• Trial-to-paid automation

Acceptance Criteria

• Trial optimization tools
• Conversion tracking
• Trial analytics
• Trial-to-paid automation
• Trial extension rules
• Trial notifications
• Trial documentation