Feature padding stack view

[huy-ras]

Add padding to UIStackView:

• theme_paddingLeft
• theme_paddingTop
• theme_paddingRight
• theme_paddingBottom
• theme_paddingVertical
• theme_paddingHorizontal
• theme_padding

[ryantan]

@huy-ras no issues with the code, but wondering if it should be on UIView. For setting isLayoutMarginsRelativeArrangement, maybe can check if the view is an instance/subclass of UIStackView and calling there. wdyt

[huy-ras]

@ryantan not sure if UIView also set up the constraints. I think should keep this simple just for stack view and for UIView that should be the constraints constant instead. Also maybe can check if the view is an instance/subclass of UIStackView I'm just think about loop all subviews -> not sure about performance.

[ryantan]

I think should keep this simple just for stack view and for UIView that should be the constraints constant instead

ok agreed.

I'm just think about loop all subviews -> not sure about performance.

Not looping through subviews, just the view theme_** is applied on.