feat: add pricing to database devops

[Sonichigo]

Thanks for contributing to the Harness Developer Hub! Our code owners will review your submission.

Description

• Please describe your changes:
  This pull request introduces a new documentation page detailing the subscription plans and pricing models for Harness Database DevOps. The page provides comprehensive information about available tiers, competitive benchmarks, subscription management, upgrade paths, and license expiry behaviors. Reference for the styling taken from - https://developer.harness.io/docs/cloud-cost-management/product-behaviour/

• Jira/GitHub Issue numbers (if any): https://harness.atlassian.net/browse/DBOPS-1481

• Preview links/images (Internal contributors only): __________________

PR lifecycle

We aim to merge PRs within one week or less, but delays happen sometimes.

If your PR is open longer than two weeks without any human activity, please tag a code owner in a comment.

PRs must meet these requirements to be merged:

• Successful preview build.
• Code owner review.
• No merge conflicts.
• Release notes/new features docs: Feature/version released to at least one prod environment.

[bot-gitexp-user]

Please check the Execution Link of the Pipeline for the Website Draft URL. This is located in the Preview Step behind the Harness VPN and also is available in #hdh_alerts. E.g Website Draft URL: https://unique-id--harness-developer.netlify.app. Current Draft URL is: https://68ac5b52303a4e1451067a44--harness-developer.netlify.app

[bot-gitexp-user]

Please check the Execution Link of the Pipeline for the Website Draft URL. This is located in the Preview Step behind the Harness VPN and also is available in #hdh_alerts. E.g Website Draft URL: https://unique-id--harness-developer.netlify.app. Current Draft URL is: https://68b1cbd210e452226f1b4852--harness-developer.netlify.app

[bot-gitexp-user]

Please check the Execution Link of the Pipeline for the Website Draft URL. This is located in the Preview Step behind the Harness VPN and also is available in #hdh_alerts. E.g Website Draft URL: https://unique-id--harness-developer.netlify.app. Current Draft URL is: https://68bac0544e52acd1e09c3096--harness-developer.netlify.app