Curation save csv button

Currently the only way to save a curated dataset is to go through every image in the `raw`/`seg1`/`seg2` folders and click next, and this saves a curated dataset as a csv in the background to the user's selected experiment.

We should explicitly allow the user to save a csv with a button in the Curation module. This will allow user to save curation dataset at any point and make things a bit more clear