Add card complete feature

[xdxd121xdxd]

When you mark a card as completed it gets moved to completed list (could be hidden or less visible than other lists)

Just make it easier to finish card.

btw. I'm using 4ga boards on a daily basis. Thanks for the tool. I've some other ideas that I'll put in the next issues.

[RARgames]

Thanks for the idea.
Right now, we have many internal feature requests and some requests from out GitHub community that are in progress.
I'll try to look at this in the meantime (cannot give any promises).

If anyone is willing to make a PR on this, I'll review it and add it sooner.