Add -filename option to rename VOD output after downloading

[Wiethoofd]

As commented here you need to manually rename the VOD file that is the result of the download & concat.

Adding a -filename option to use that as preferred filename after concat when provided could be nice to have. (While still keeping the Twitch VOD ID for the temp folder; so resuming downloads still works even when the filename option isn't provided for a 2nd attempt).

[kirides]

When i find time, i might add a PR for the Stream name

meanwhile on my own fork, there is resuming downloads (using http-Range requests), stream title, downloading also by Url instead of only id progress-bar, downloading multiple vods (removed the -vod flag, concat [OPTIONS] idOrUrl ... nIdOrUrl )