docs: Add pagination explanation to docs

[filinvadim]

Resolves #2133.

Summary
This addition to the documentation provides a detailed explanation and implementation of pagination using prefix scans for lexicographically sorted keys.
Introduces a practical method for implementing pagination using:

• A limit on the number of results returned per query.
• A cursor (last processed key) to track the stopping point of the current iteration and resume subsequent queries.
  Includes a clear example of using cursors to manage iteration over keys in BadgerDB.
  Provides a complete Go implementation, showcasing how to perform prefix scans, manage pagination, and retrieve key-value pairs sequentially.

This addition enhances the documentation by offering both theoretical insights and practical guidance, making it easier for developers to implement efficient, scalable, and sorted data retrieval mechanisms in their applications.

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[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

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