Fix/optimize tests & general setup

[backflip]

Setup:

• Updated all npm dependencies to latest → This fixes issues on Travis. For some reason it was installing newer dependencies than my machine.
• Added missing dependencies and moved some devDependencies from root to projects
• Disabled package lock files (not necessary for development of packages)
• Bumped Node to 10
• Added npm run update using npm-check to update dependencies in both root and every package
• Travis: Updated Node versions, increased Lerna loglevel

Tests:

• estatico-sass: Fixed tests to properly finish
• estatico-imageversions: Reduced precision in image comparison, optimized error handling
• estatico-webpack: Updated test fixture
• estatico-eslint: Removed test fixture from linting config

Chore:

• estatico-scaffold: Linted code