Added methods to expose Video struct basic attributes

[AndreaNicola]

For one of my projects I needed to extract the dimensions and duration from the video.

I realized that these fields were present within the Video struct and therefore, without using other libraries, it is convenient to expose these 3 new methods to retrieve the field values effortlessly.

Bye :-)

[HGriessel]

Hi Andrea,

I know this is unconvetional I am a semi expereinced python developer learing go.

I however want to start contributing to Opensource and this project does seem like a good entry point and would like to find out if you would be available for conversation on this.

[AndreaNicola]

😃

[mowshon]

@AndreaNicola Thanks for participating! I will analyse the changes and make sure to commit to them. I'm very happy to have your help!

[mowshon]

Approved the changes, but I'll remove the Get prefixes from the methods.