Develop a cytotable.annotate function to incorporate metadata

Based on the tests, it seems like the convert function should work the same as using Pycytominer `Single Cells`, where we merge the single cells from the database with the corresponding metadata.

After running this function, I can see that this was not the case.

For clarification, should the `convert` function be able to merge single cells (e.g. with the compartments being able to associate the objects together to get a file with all single cells) along with converting to parquet?