feat: add support for download options

[MagnusHJensen]

What kind of change does this PR introduce?

Adds new support for download options to allow GetPublicUrl, ´CreateSignedUrlandCreateSignedUrls` to support generating a url which contains download options.

What is the current behavior?

No support.

What is the new behavior?

Support for it, by adding a nullable options field to those method, to avoid breaking changes.

My first thought was to include a boolean and a string value, but it's just a weird way to do it, so I instead relied solely on the FileName attribute to check if we should set download - where "" defaults to =true aka. original file names as they are in the bucket.

If this approach is not preferred in it's current form another way could be to add a virtual setter, for a boolean field that sets the FileName field behind the scenes, so we still only rely on one field?

Additional context

closes: #17