Duplicate buttons

[firdiar]

it is quite essential after working with this package for a long time, sometimes i want to use the animation steps for other object as well, but need to repeating the config is tiring. so i add duplicate button.

i think in the future, 'copy button' also a good to have feature, so we can copy the step config to another sequencer

NOTE: Feel free to reject the PR if not to your liking