Proposal: refactor S3 to use an object oriented pattern

[MoralCode]

it seems like all the calls to s3 are passing a global object into them

Seems like it may be better to create an S3 class to handle all the s3 operations (which would set up nicely for #17 )

I have already made this change on a local branch that depends on several other branches so i know it works (oh and i migrated S3 over to boto3 and it works as far as i can tell)

[MoralCode]

My PR for this currently depends on #29. i could probably refactor it to avoid this if need be, but if #29 is gonna get merged id rather not waste the effort.

also i developed this while trying to do the boto -> boto3 migration. I could maybe separate it into two PR's if you'd rather tackle it in stages, but again, wanted to check before going through the effort