Refactor env variables usage

[SanjoDeundiak]

Currently, there is a standard way to obtain an env variable implemented here. There are 3 different ways to call that API depending on desired behaviour. The goal is to review where that API is used and unify its usage when an invalid env variable value is present. The correct behaviour is following:

1. Print an ERROR level warning to the log and return the default value, if we can't propagate the error all the way to the user
2. Return an error if we can propagate it all the way to the user

[ilyaaay]

Hi. I want to take this issue

[SanjoDeundiak]

@ilyaaay all yours