Feature: Create main variables file

[StraykerPL]

Is your feature request related to a problem? Please describe.
Some of repeatable styling data, like fonts, font sizes, colors etc. are used along howl project. Statically repeating this values breaks DRY rule.

Describe the solution you'd like
Angular is compatible with centralised _variables.scss for storing Sass variables.

Describe alternatives you've considered

Additional context

[StraykerPL]

Blocked by #9

[StraykerPL]

Unblocked