Add an option to the API to ignore/refresh the file cache

[apdavison]

for example, suppose the file at a given URL is exchanged for another with the same name

[appukuttan-shailesh]

This would be a handy feature. But it will still require web pages (making use of neo viewer) to be kept track of and updated (with this option) when a particular file is changed. At the time of creating the webpage, authors might not anticipate changes and would prefer to make use of the caching feature for performance reasons. And eventually they are likely to forget the caching aspect. It might be useful to consider caching to be disabled as default, or have some minimal checks such as if the file size has changed (via HTTP HEAD method; not foolproof but some basic check) .

As example, for the file located at:
https://object.cscs.ch/v1/AUTH_c0a333ecf7c045809321ce9d9ecdfdea/EBRAINS_live_papers/2018_migliore_et_al/exp_data/abf-int-bAC/Ivy_960711AHP3/96711008.abf

HEAD retrieves the following info:

I believe we can make use of "Content-Length" and "Last-Modified" to compare if the cached file is same as the file currently at the target URL, as some basic check (which should probably suffice for our purposes).