WIP: Add GUI changes to show composer repository paths and copy button

What does this MR do?

Add endpoint/repository information for package_type composer

1. Allow to copy install command e.g. composer required vendor/package
2. Copy instance endpoint path
3. Copy group endpoint path

Example for 2. and 3.:

"repositories": [
	{
		"type": "composer",
		"url": "http://192.168.178.42:3001/api/v4/packages/composer/"
	}
],

What are the relevant issue numbers?

See gitlab-org/gitlab-ce#22079 and gitlab-org/gitlab-ee!9012

Does this MR meet the acceptance criteria?

• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• [-] Conforms to the database guides
• EE specific content should be in the top level /ee folder

Status

• Waiting for !17417 (closed) to be merged.