Clearing write directory when re-bundling

[scheul93]

Currently, the plugin does not clear the write directory when re-bundling. This can lead to older deprecated bundles being left in the directory.

For project maintenance sake, it would be better if the plugin cleared out the write directory first.

[heaper]

This can be accomplished with rollup plugins like rollup-plugin-delete. Closing this ticket, but I'll add a ticket to the relevant orko templates.