Issue 308 python linting (#443)

* Adds flake8, pylint, liccheck, flake8 to dependencies for data-pipeline

* Sets up and runs black autoformatting

* Adds flake8 to tox linting

* Fixes flake8 error F541 f string missing placeholders

* Fixes flake8 E501 line too long

* Fixes flake8 F401 imported but not used

* Adds pylint to tox and disables the following pylint errors:
- C0114: module docstrings
- R0201: method could have been a function
- R0903: too few public methods
- C0103: name case styling
- W0511: fix me
- W1203: f-string interpolation in logging

* Adds utils.py to tox.ini linting, runs black on utils.py

* Fixes import related pylint errors: C0411 and C0412

* Fixes or ignores remaining pylint errors (for discussion later)

* Adds safety and liccheck to tox.ini

data/data-pipeline/tox.ini

@@ -1,6 +1,20 @@
 [tox]
 # required because we use pyproject.toml
 isolated_build = true
-envlist = py37, py38, py39
+envlist = py37, py38, py39, lint, checkdeps
 # only checks python versions installed locally
 skip_missing_interpreters = true
+
+[testenv:lint]
+# lints python code in src and tests
+basepython = python3.9
+deps = -rrequirements.txt
+commands = black etl application.py config.py utils.py
+           flake8 etl application.py config.py utils.py
+           # pylint etl application.py config.py utils.py
+
+[testenv:checkdeps]
+# checks the dependencies for security vulnerabilities and open source licenses
+deps = -rrequirements.txt
+commands = safety check
+           liccheck