Add more linting rules to golangci.yml

[lumtis]

Describe the Issue

Add more linting rules and fix the errors that would arise from it.

    - gosimple     # Detect simpler code constructs
    - staticcheck  # Provides robust checks for common bugs

Check revive rules: https://revive.run/r

Find something for undocumented code https://revive.run/r#exported ?