Fix linting errors

[jmadden173]

With more people working on the project its finally time to following the linting guidelines. They'll help keep the style consistent throughout the project and make it easier for new people to understand the repo. The google c++ style guide has a configuration for cpplint and is included in requirements.txt. I listed everyone with a user code library that I felt was most applicable to what they are working on right now. For the library you are assigned the errors that show up in the linter will need to be fixed included corresponding example and test files. Each library should have its own branch name prefixed with fix-lint- and you can list me as a reviewer.

Steps to lint

Create venv if not already created

python -m venv .venv
pip install -r requirements.txt

For stm32

cd stm32
cpplint --recursive lib Src/examples test

For esp32

cd esp32
cpplint --recursive --root=. Inc Src lib test

Assignments

ads - @ahmedfalah01 battery - @2004Island fram - @stevegtaylor phytos31 - @Kshitijpatil16 sdi12 - @gxjacobs sensors - @jmadden173