Add logic for removing any parent flex items, regardless of order.

[rabbitwerks]

So far the app has the Add/Remove logic for the parent flex items, but this only affects the last flex item present. we need to add logic to be able to remove a specific flex item, regardless of where in the order of items it is.

A simple event handlers could do the trick or incorporate it into either the parent flex item itself or the context (more options) menu.

view the app at: https://rabbitwerks-flexbox-playground.netlify.app/#/playground