i18n item URL copy notification & add Japanese message

[HiroyasuNishiyama]

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Proposed changes

Notification message of copy item URL is not i18n ready.
This PR tries to make it i18n ready and adds Japanese message.

Checklist

• I have read the contribution guidelines
• For non-bugfix PRs, I have discussed this change on the forum/slack team.
• I have run grunt to verify the unit tests pass
• I have added suitable unit tests to cover the new/changed functionality

[coveralls]

Coverage decreased (-0.006%) to 68.186% when pulling b95df6d on node-red-hitachi:i18n-item-url-copy-notification into 7da3773 on node-red:dev.