[Enhancement] Simplfy the content on payment intent and payment attempt explanation

The content in [this section](https://opensource.hyperswitch.io/learn-more/payment-flows#what-are-paymentintent-and-paymentattempt-objects-and-how-do-they-work-in-hyperswitch) is difficult to navigate and understand. There are two diagrams for each concept and not able to relate both.

Solution:
1. Single high level diagram to explain payment intent and payment attempt flow
2. Include information on the data stored under payment intent and payment ID