Angular widgets apis refactor

[quentinderoubaix]

Context Following our discussion regarding the angular widgets apis, we have decided that angular widgets should obey the following rules:

• the selector should not be 'au-$name' but '$htmlElement au$Name'
• every input and output should prefixed with au

Example of change For the rating default, this would mean going from:

<au-rating [(rating)]="rating" (hover)="hovered = $event" (leave)="left = $event" ariaLabel="rating" />

to

<div [(au-rating)]="rating" (au-hover)="hovered = $event" (au-leave)="left = $event" au-aria-label="rating"></div>

[divdavem]

As discussed today with @quentinderoubaix, maybe we should rather finally use camelCase:

<div [(auRating)]="rating" (auHover)="hovered = $event" (auLeave)="left = $event" auAriaLabel="rating"></div>

That's what people are used to for attributes in Angular, and also otherwise, it is strange to have a mix of kebab-case and camelCase for bindings (i.e. (au-ratingChange)=... which is mandatory if we want to support [(au-rating)]="rating").