Only add existing script and link tags when transferring the document head

[agubler]

Type: bug

The following has been addressed in the PR:

• [x] There is a related issue
• [x] All code has been formatted with prettier as per the readme code style guidelines
• [x] Unit or Functional tests are included in the PR

Description:

Only add script and link tags from the output index.html, instead of copying over the entire document head after build time rendering.

Resolves #287