Ability to clone panels

[bobrik]

Our default dashboard has histogram panel with customised settings. Sometimes managers need to have two-three-five panels like this, but with different attached queries.

Now they need to create new row, add histogram panel, change all settings to match existing panel and attach queries. It would be nice to have an ability to simply clone the panel or even the whole row to make it easier.

[bwmeier]

Exactly 👍 There's several layers of defaults that could be implemented here to make dashboard configuration easier. See also #886 :-)