Support SVG files

Gallery is mainly renderer in a <img? tag. The problem with SVG is that the browser needs to know that the file is a SVG so it can render the img accordingly. The current endpoint does not give a clue about the kind of object the resource is: https://icatplus.esrf.fr/resource/{sessionId}/file/download?resourceId=647f6600848ef400124c8cf3

As alternative it could be used the tag object which can contain the type:

<object type="image/svg+xml" data="myFile.extension"></object>

However, this approach misses the img properties, lazy loading, zoom, etc...