docs: Add wasm manifest content to splash screen feature docs

[lukeblevins]

GitHub Issue (If applicable): contributes toward #14805

PR Type

What kind of change does this PR introduce?

• Documentation content changes

What is the current behavior?

Bootstrapper-oriented doc overlap with existing feature content.

What is the new behavior?

Improved the general feature doc to contain content based on a topic in the wasm bootstrapper repo

PR Checklist

Please check if your PR fulfills the following requirements:

• Docs have been added/updated which fit documentation template (for bug fixes / features)
• Unit Tests and/or UI Tests for the changes have been added (for bug fixes / features) (if applicable)
• Validated PR Screenshots Compare Test Run results.
• Contains NO breaking changes
• Associated with an issue (GitHub or internal) and uses the automatic close keywords.
• Commits must be following the Conventional Commits specification.

Other information

@jeromelaban Assuming these changes are acceptable, would it make sense to remove/repurpose the existing article last edited 2 years ago?

Internal Issue (If applicable): N/A

[unodevops]

🤖 Your Docs stage site is ready! Visit it here: https://unodocsprstaging.z13.web.core.windows.net/pr-15244/index.html

[jeromelaban]

@Mergifyio backport release/stable/5.1

[mergify]

backport release/stable/5.1

✅ Backports have been created

• #15288 docs: Add wasm manifest content to splash screen feature docs (backport #15244) has been created for branch release/stable/5.1 but encountered conflicts