Add support for `mini.pick` as a picker

[pkazmier]

With mini gaining in popularity, this commit adds support for mini.pick.

Here is a short screencast showing this new picker in action with Zk notes:

https://github.com/zk-org/zk-nvim/assets/747855/cf645482-c3eb-4713-8925-bb1501f54cb8

[tjex]

Although we've gotten through all the bugs for zk-nvim, I would consider us still in maintenance mode (as per the readme) until we cut a new release of zk. This should realistically be quite soon, at which point we may want to look at starting with release versioning with zk-nvim as well.

I would say we should continue holding off on all feature request PRs until the above has happened?

I agree that it would be great to get @kabouzeid 's input.

[pkazmier]

Refactored the code to address all of your comments: multi-select, padding, etc ...

[kabouzeid]

thanks for the contribution!

[pkazmier]

Thank you!