Feature: Exlude files based on their extension

[JanDeDinoMan]

Hello first of all thank you for your great extension!

This PR adds the possibility for users to exclude certain file extensions. Sometimes when working on projects you can be working with files where the licenses don't make much sense. Therefor it can be a nice feature to have to possibility to disable the automatic header insertion for them only. As for now you only have two options: Delete the header every time or disable the auto insertion. And of course this is completely optional so current behavior isn't changed.

I hope you consider my addition.

[JanDeDinoMan]

Hmm after some thinking this now only filters based on extension. However it could also be a option to introduce two new settings to exclude files from auto insertion:

• useGitignore (this respects the .gitignore of the project)
• excludeRegex (have an array with additional regex rules)

Maybe this would be a better solution, or is this PR fine?

[DrJStrudwick]

@ymotongpoo Any updates on this, seems like it would be a really beneficial add on