Make CodeClimate config more strict
Make CodeClimate config more strict

There's no point of using Code Climate if most of its checks are
disabled. Now it scores our codebase with an A and reports just 2 code
smells, 64 duplications and 14 other issues. That couldn't farther from
reality. If we care about the architecture and maintainability of our
app, this is a must.

To transition towards enabling all default checks, I started with
scss-lint, duplication and method-complexity. This doesn't mean will
have to fix them all straight away as we'll add the current violations
to the `.rubocop_todo.yml` but it'll point us the parts where we should
focus our efforts.

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