Added file size for packages

[cacciatc]

PR to address: KnightOS/KnightOS#305

A couple notes:

• Added a new column to the package table for tracking the number of bytes. Therefore the db needs to be migrated.
• New and version bumped package uploads have their file size calculated on upload.
• All existing packages can have their file sizes calculated and saved in the db by running
  
  python manage.py calc_package_file_sizes
• Accordingly, I added a new dependency flask-script in order to do so (therefore updating w/ pip may be in order).
• The file size is saved in bytes and displayed as KB. KB seemed to be the best fit based on the packages I looked at.

[cacciatc]

Howdy,

Was going through my older PRs and saw this one. Any questions you need answered or suggested changes?

[ddevault]

Sorry, this one is just complicated to deploy so I've been holding off on reviewing it until I have time.