feat(Search): OnSearch callback support async

[ice6]

Is there an existing issue for this?

• I have searched the existing issues

Is your feature request related to a problem? Please describe the problem.

I want to search my index on elasticsearch using this component, but now it seems I can not.

I want to customize the dropdown item's UI, but now it seems I can not.

Describe the solution you'd like

1. make the component's data provider as async function, so the user can have a flexible way to provide data.
2. make the dropdown items's ui customizable.

Additional context

it may have quite lots of work.

[bb-auto]

@ice6 Thank you for contacting us. We will give feedback later.

[ArgoZhang]

@ice6 SearchBox ? which component? please provider a Url on wwww.blazor.zone

[ice6]

@ArgoZhang sorry, it is search. https://www.blazor.zone/search

[ArgoZhang]

@ice6 redesign Search component

1. remove Items parameter
2. update OnSearch callback support async

please take a look of sample code https://www.blazor.zone/search#ItemTemplate