Closes #3843 Add Lazyrender Content feature

[wordpressfan]

Description

Fixes #3843
Explain how this code impacts users.

Type of change

• New feature (non-breaking change which adds functionality).
• Bug fix (non-breaking change which fixes an issue).
• Enhancement (non-breaking change which improves an existing functionality).
• Breaking change (fix or feature that would cause existing functionality to not work as before).
• Sub-task of #(issue number)
• Release

Detailed scenario

https://www.notion.so/wpmedia/Lazy-render-content-bf707b5f731a426cb5d1294beb770540?pvs=4

Technical description

Documentation

https://www.notion.so/wpmedia/Lazy-Render-Content-LRC-7de60c101f0344f2a6280dd2e0f019c2?pvs=4

New dependencies

DOMDocument

Risks

NA

Mandatory Checklist

Code validation

• I validated all the Acceptance Criteria. If possible, provide screenshots or videos.
• I triggered all changed lines of code at least once without new errors/warnings/notices.
• I implemented built-in tests to cover the new/changed code.

Code style

• I wrote a self-explanatory code about what it does.
• I protected entry points against unexpected inputs.
• I did not introduce unnecessary complexity.
• Output messages (errors, notices, logs) are explicit enough for users to understand the issue and are actionnable.

Additional Checks

• In the case of complex code, I wrote comments to explain it.
• When possible, I prepared ways to observe the implemented system (logs, data, etc.).
• I added error handling logic when using functions that could throw errors (HTTP/API request, filesystem, etc.)