UI: Chips components for Chat

[mimetic]

Feature / Issue

To start a new chat, we need to choose people from a list.
When a person is chosen, their name appears as a "chip", a Material Design component. (see bottom of this issue for URL and details.)
We need working "Input Chips"

Acceptance criteria

• Styled chip component, with functionality for "cancel"

Additional information

Here are the detailed spec's on chips! This will give you pixel measurements, states, etc. — everything you need.
See the section on Input Chips: placement, to see stacked chips.

https://material.io/design/components/chips.html#specs

[seland]

Accidentally created a duplicate of that - #505. However, since we're going to use library instead of implementing it ourselves, I'm closing that issue in favor of new one.