Enhancement: Config function

[Weyaaron]

This function should allow users to configure some aspects of the plugin. In particular, the following has to be done:

• [ ] Expose a function to the users
• [ ] Create a data-structure that contains the values
• [ ] Implement the code that interacts with the config
• [ ] Document it

[Weyaaron]

This has been done in https://github.com/Weyaaron/nvim-training/commit/faff202eccc5c2dd2827a9c77a1aae9e8a25d1fe