Add basic backloggery pulling functionality

This commit adds the ability to pull down the html for a backloggery
collection. It does not support pulling down info about collections.
There's a log of WIP stuff here.
Remake template strings to allow for more logical separation

This commit also includes some docstrings for the BackloggeryRequester
class (a class I will soon rename). The general idea behind the Template
changes was to use less substitutions during the loop step.
Refactor BackloggeryRequester class to GamesRequest