rethinking saving mechanism

[ianhi]

Currently saving here defaults to a basic tiff saving. Eventually that will probably live in pymmcore-plus, but that would still limit the saving option in the MDA dialog to a single method of saving.

Given that anyone will be able to create objects to handle saving (e.g. my raman zarr writer) it would be amazing to provide a mechanism for napari-micromanager to allow users to select from any supplied package.

I imagine this going like this:

1. pip install my-writer
2. napari-micro discovers the provided writers via entrypoints (or pluggy or ???)
3. Option for that writer provided in the MDA dialog
4. use magicgui to generate dialog to set any creation options for that writer