perf: use http2 connections for serverside fetching

[Rdataflow]

Is your enhancement related to a problem? Please describe. currently serverside node-fetch only uses http/1.1 connections to fetch http(s) requests.

Describe the solution you'd like a serverside method (re)using http/2 connections for http(s) requests i.e. SPARQL requests.

Describe alternatives you've considered continue using legacy http/1.1 w/o multiplexing

Usecases and impact reusing connections and multplexing for serverside fetching i.e. SPARQL requests

Additional context i.e. https://www.npmjs.com/package/node-fetch-h2 or whatever devs prefer to use more context on reusing connections at https://www.sohamkamani.com/nodejs/http2/#http2-connections-and-sessions