[Render plugin] Performance improvement opportunity with memoization of `renderFile` shortcode

[nhoizey]

Is your feature request related to a problem? Please describe.

As mentioned in another issue about the Bundle plugin bundling assets multiple times even with the same content, I recently added memoization to the compile functions of my custom formats and improved my build time a lot.

Building my photography site on GitHub Actions used to take around 17 minutes, and it now takes less than 6 minutes (still a lot 😅, but much less).

Describe the solution you'd like

I wonder if memoization of the renderFile shortcode could be automated in the Render plugin, based on inputPath and/or a hash of inputContent.

Describe alternatives you've considered

Every one can add memoization to his own code.

Additional context

No response