[Proposal]: Add ffmpeg creationflag in Writegear API

[abhiTronix]

Issue guidelines

• [X] I've read the Issue Guidelines and wholeheartedly agree.

Issue Checklist

• [X] I have searched open or closed issues and found nothing related to my idea.
• [X] I have read the Documentation and it doesn't mention anything about my idea.
• [X] To my best knowledge, my idea wouldn't break something for other users.

Describe your Idea

See #375 for reference I propose a new feature to enable detached subprocess creation on Windows within the writegear module. This enhancement enhances the process management capabilities of the module.

Use Cases

See #375 for reference This can be useful while creating an exe file for a python script that uses writegear. On windows even after creating the exe file in windowed mode or no-console mode, the ffmpeg.exe command line window would pop up while its being used by write gear.

[abhiTronix]

Successfully resolved and merged in commit https://github.com/abhiTronix/vidgear/commit/3c0dd5d482e5eba37b41a5a2422f65f856e0f27c