feat: add support for chips in input

# Feature Request

**Ionic version:**

[x] **4.x**

**Describe the Feature Request**
Support grouping of chips - input type specifically.

**Describe Preferred Solution**
I need to look into the best way to handle this. I think we may need to add an `ion-chip-group` similar to how radio works.

Usage - https://material.io/design/components/chips.html#usage
MD implementation - https://github.com/material-components/material-components-web/tree/master/packages/mdc-chips#adding-chips-to-the-dom
MD demo - https://material-components.github.io/material-components-web-catalog/#/component/chips

**Describe Alternatives**

**Related Code**

**Additional Context**

Start by reviewing the existing chip and radio component patterns, then compare the proposed ion-chip-group behavior with the linked Material Design references. Define the grouping API and input-chip interaction requirements before identifying implementation files and tests; done means grouped input chips work as specified and are covered by tests.

索引モデルが issue の本文から書いたものです。