hfetch - reinstate the cacheBuster functionality.

[jesade-vbg]

The cacheBuster fuctionality was disabled little over a year ago because we updated to webpack 5 which does not have support for process.env.

The cacheBuster fuctionality in hfetch should be reinstated again.... somehow.... with or without process.env.

Today, the code is just commented, and forgotten.

this.useCacheBuster = process?.env?.REACT_APP_USE_CACHE_BUSTER === "true" || false;