feat(Avatar): added children prop

[js2me]

• refactored (removed renderContent function)

[gravity-ui]

Preview is ready.

[gravity-ui]

Visual Tests Report is ready.

[amje]

@js2me What's the purpose of this?

[js2me]

@amje customization.
In my project I want to add loading statement for this avatar component, otherwise I should create full copy of this component to add "children" prop.

[amje]

@js2me Not sure if it's a proper API. Avatar has a strict appearance set by the design system and does not imply arbitrary content. Allowing any content can break component in many different ways.

[js2me]

@amje ok, but why className is allowed for this component if "has a strict appearance set by the design system and does not imply arbitrary content" ? Using this prop I can customize apperance of this component.
Also I do not understand why UIKit has a lot of components which accepts children as prop but this option is not allowed for this component

[amje]

@amje ok, but why className is allowed for this component if "has a strict appearance set by the design system and does not imply arbitrary content" ? Using this prop I can customize apperance of this component. Also I do not understand why UIKit has a lot of components which accepts children as prop but this option is not allowed for this component

@js2me className main purpose is to mix with your classes in order to set margins or other outer layout styles. children is available only for components without own content, Avatar already has its content defined via other props