Added Frames and GOP Timecode Side Data Support

[Hendo16]

Closed my previous PR as I hadn't removed the restricted frame output, as well as not fully building out the Frame struct.

Noticed that there wasn't any support to detect I-Frames with this library so quickly added arguments to the command that'll add it to the JSON output as well as building up the matching structs

[vansante]

So I had a little look, and codewise, everything seems in order. However, I am seeing a potential problem in the amount of data this extra option is going to generate:

-show_frames

Show information about each frame and subtitle contained in the input multimedia stream.

The information for each single frame is printed within a dedicated section with name "FRAME" or "SUBTITLE".

The amount of frames in some longer videos is going to be immense, and I would like this to remain a fast utility to grab information about media files. If we enable this by default, things will end badly on that end.

(For reference, the included test file test.mp4, which is just over 1 MiB, already clocks in at 381 frames 😅)

So I am fine with including the frame support JSON structs and all, but I don't think we should enable this option by default.

[Hendo16]

Fair enough! Appreciate you checking this out - will update this so the option is removed from the default list of options

[vansante]

Can you perhaps write a separate test with one of the test files in assets with the -show_frames option set and a test the structs are as expected?

(And please fix the CI thingy about capitalization)

[vansante]

Can you explain why/how this can be a string?
FFMpeg vbv_delay

And since this is the only place we use FlexInt, maybe we dont need it then?

[Hendo16]

VbvDelay can be an integer or a string. I've encountered cases where it's either 0, -1 or "N/A" so parsing it just as an int doesn't work and needs to be handled accordingly. Maybe the better solution is just parsing the integers to a string as well?

[Hendo16]

Sorry for the mess of commits - I fixed the capitalization issue and added some tests but for the life of me I can't figure out why the linter isn't working. It says there's a version mismatch so I tried updating the go.mod but then then that resulted in another error so i'm going to leave this for now.