Feat/cancel upload by video id

[Shreedhar73]

The current cancelAll methods, cancels all the current uploads .

Implementation of Cancelling the Video Upload using the video ID. Useful when, a video object is created before starting the upload process.

[ThibaultBee]

Hi there,
Thank you for your PR.

This PR concerns videoId that's mean you are using an API key in your application. Make sure you read https://docs.api.video/sdks/security#securing-the-api-keys-on-the-application-not-recommended before.
TL;DR: Don't use API key and videoId but use upload tokens.
For this reason, we probably won't merged it.

Now on your PR itself:

• The Android implementation is good
• The iOS implementation seems to be a little odd, storing a list where a lot of items could be blank value seems really strange. I think using a dictionnary would be a better implementation. It is also missing the progressive upload part.
• The web implementation is missing.