Feature request: add repository size statistics to "Software Report"

[davenquinn]

I recently completed a JOSS review (openjournals/joss-reviews#8812 (comment)). In downloading the repository I discovered it was very large due to old commit blobs.

If it is straightforward, it might be nice to flag such issues in the Software Report, by integrating a command to print the basic size of the repository (both the working tree and commit history).