refactor(Buttons) implement buttons styling with mixin

[gselderslaghs]

Proposed changes

Refactored buttons styling with scss mixin, to make it reusable in #565 #566

Types of changes

• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to change).

Checklist:

• I have read the CONTRIBUTING document.
• My commit messages follows the conventional commit format
• My change requires a change to the documentation, and updated it accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[wuda-io]

I don't know about mixins, but if it makes the styles reuseable, then i am ok with it.

[gselderslaghs]

I don't know about mixins, but if it makes the styles reuseable, then i am ok with it.

It will make the styles reusable and as a result will reduce duplicate code fragments. The mixins provides additional ways to create buttons with variable arguments as you can see in this example within the cards component, in this example the global button vars are being used, it can be set with custom value arguments as wel

[wuda-io]

This variables were used as helper vars once. They were not intended to be used as global style vars. Also long-term I think it is better to use css only approach and move away from scss and mixin functions. We can merge for now...