New component: mgt-search

[elisenyang]

Proposal: Create a generic picker component

Description

Build a generic picker that supports a predefined list of Graph entities (ex: Files, People, Messages, Channels, Sites, etc.). The developer should be able to choose which entities to include in their app. We should also explore making the picker easily extensible for new entities.

Rationale

We have been getting multiple feature requests to build a picker for "x". This will allow us to resolve many of these requests with one solution.

Preferred Solution

TBD. Needs spec.

Additional Context

[waldekmastykarz]

Will the UX experience be the same for all entities (ie. search as you type + drop down with matching items + input box with selected items inline; kind of what we have for the people picker today)? If so, the picker could be as generic as letting people specify the resource to query to get a list of items, and then specify a template to render one item. That way, we wouldn't restrict folks to a specific set of entities and they could pick anything they want in a consistent way.