Yew Function Component Support

[futursolo]

This issue aims to experiment with hooks API that will be adopted with the upcoming function component for Yew 0.19.

[futursolo]

There're two sets of APIs that will be introduced:

1. use_style and use_style! API.
   The function flavour of this hook will accept the same argument as Style::new and the macro flavour will accept the same argument as the upcoming procedural macro.

2. styled_component(MyComponent) + css!

This API will introduce a styled_component attribute which will be equivalent to the original function_component from yew but also injects a manager instance with use_context at the beginning of the function component.

Purposed Syntax:

use stylist::yew::styled_component;

#[styled_component(MyComponent)]
fn my_component() -> Html {
    html! {
        <div class=css!(r#"color: red;"#)>
            {"Styled Text!"}
        </div>
    }
}

(The syntax for the css! API is tentative as procedural macro is not landed on master yet.)

Both APIs will be context aware.

[WorldSEnder]

I'm currently experimenting with having a branch that tracks yew@next until the release of 0.19. This could then host the hooks implementation. Current show stopper is yewdux not being updated to yewstack/yew#1961 yet. Guess it has to wait a bit.

[WorldSEnder]

The working parts live on the yew-next branch now

[futursolo]

I do plan to cut at least one more release before introducing hooks (switching to track yew master) so I am fine with it lives on a different branch for now.

[futursolo]

As per yewstack/yew#2052, I think the Yew 0.19 release is imminent.

I have updated the master branch to track master branch of Yew and implemented the styled_component API.

So as soon as Yew 0.19 is released we can release a version with function component support.

[futursolo]

The Yewdux and yewtil::store example have been replaced with Context API Example.