Thanks for the input!
I didn't mean to add each individual read in the database! I just want to be able to download the fastq files of each run. As for the assembly/annotation handling, what I want is to be able to keep, for example, different assembly versions (eg uncorrected and corrected versions), or to be able to extract all protein sequences of the annotated genes that match some particular criteria. I also don't necessarily need a visualization of the genomes.