Create loading version of `InputField`

[PavelHolec]

A loading() (similar to modifiers like disabled()) should be supported on components that may need a loading indicator (InputField, Button,...)

It probably should also contain a disabled() modifier inside by default.

Signature

loading(_ isLoading: Bool, isDisabled: Bool = true)

Kiwi.com code

InputFieldLoadingModifier.swift

[sjavora]

Depends on iOS 14 only ProgressView