Resolve "convert sheetload to the singer tap spec"

Closes #1 (closed)

CLI tasks

• create a cli file
• add create_keyfile command
• add an extract command

Client tasks

• create a gsheet client
• client authenticates on init
• gsheet client reads one sheet at a time and then returns result (a generator maybe?)

Setup/infra

• dockerfile
• makefile
• setup.py
• requirements

Finishing touches

• write tests foregoing tests for now as the make run command actually touches every part of the code. as features are added though it will be important to add tests
• create README
• get rid of the catalog and instead put a sheets section in the config that is a list of sheets to load following the sheet#tab syntax. it will assume that the ID is just called id for every sheet and that the stream name is the tab