Feature: extension config

[Myrfion]

Config is a good thing to have in an extension that will increase the range of possible features that could be implemented and will help to customize the behaviour of the extension for each user. For example, in the previous issue #5 I created a snippet that allows users to make a head for their file with their student info. It would be amazing if the extension would take their data from the extension config and automatically place it. This is what vs code doc says about extension config

An extension can contribute extension-specific settings with the [contributes.configuration](https://code.visualstudio.com/api/references/contribution-points#contributes.configuration) Contribution Point and read them using the [workspace.getConfiguration](https://code.visualstudio.com/api/references/vscode-api#workspace.getConfiguration) API.

Refer here for more information