Tests for API modules

Created by: HighSaltLevels

What/Why

Saltbot has no tests :(

This PR is one of many to add tests as well as coverage. This PR not only adds tests for giphy.py, youtube.py and api.py, but it also adds a test runner bash script, coverage call, and an updated .gitignore for developer related folders like .venv and .coverage

Testing

Name                    Stmts   Miss  Cover   Missing
-----------------------------------------------------
saltbot/__init__.py         0      0   100%
saltbot/__main__.py         5      5     0%   4-11
saltbot/api.py             24      0   100%
saltbot/commands.py       189    189     0%   3-374
saltbot/controller.py      39     39     0%   2-61
saltbot/giphy.py           20      0   100%
saltbot/logger.py          19     19     0%   4-32
saltbot/poll.py            72     24    67%   92-124
saltbot/reminder.py       125    125     0%   4-221
saltbot/timelength.py      15      0   100%
saltbot/version.py          1      1     0%   3
saltbot/youtube.py         20      0   100%
-----------------------------------------------------
TOTAL                     529    402    24%