add quicklink for youdao.com

[SteveLauC]

This PR will remain a draft until full support for Quicklink is implemented.

[SteveLauC]

This section of doc should be updated:

coco-extensions/docs/README.md

Lines 95 to 109 in 9ece0d2

	* `type`: Extension type. For third-party extension, the following types are
	currently supported:
	* `extension`: An extension of type `extension` behaves like a folder, i.e., a
	container for sub-extensions.
	Currently, sub-extensions should be of type `command`, which should be set in
	the `commands` field.
	* `command`: `command` executes a command when being executed. This action
	will be specified by the `action` field.
	type: enum
	required: **Yes**