[Table] Add inline editing for inputs

#### Bug, feature request, or proposal:

Feature request

#### What is the expected behavior?

Clicking on a text field should launch a simple edit dialog with an `md-input`. Hitting Enter would then close the dialog and save the input as the new value for the text field.

#### What is the use-case or motivation for changing an existing behavior?

This behavior is described in the Data Table section of the Material spec, found [here](https://material.io/guidelines/components/data-tables.html#data-tables-interaction), and would be useful to have as its own component.

#### Is there anything else we should know?

Accessibility is a real concern here, and there doesn't seem to be much discussion/affordance defined in the spec for possible solutions. The text field itself could be defined as a button with `aria-role="button"`, but that may be deceptive.

cc @andrewseguin @jelbourn

まず、要求されたインタラクションとリンク先の Material のデータテーブル仕様を確認します。関連するテーブルと入力のエントリーポイントを特定する前に、アクセシビリティの方針を決めてください。完了の条件は、テキストフィールドで編集ダイアログが開き、Enter で新しい値を保存してダイアログを閉じ、インタラクションにアクセシビリティが確保されていることです。

索引モデルが issue の本文から書いたものです。