fix(sass): right dimensions for buttons learned from VK Design Requirements guide
fix(sass)!: btn-big -> btn-lg
fix(sass): select the right Roboto font's variant
fix(sass): buttons without rounded-х classes are square by default
feat(sass): introduced mini-widget style with no-text className
fix(vk-signin-button.tsx)!: remove "label" property since VK required predefined strings in the button