UHF-10535: updated typography variables, added letter spacing

[annadruid]

UHF-10535

What was done

• Changed typography line heights and added letter spacing to some

How to install

• Make sure your instance is up and running on latest dev branch.
  • git pull origin dev
  • make fresh
• Update the HDBT theme
  • composer require drupal/hdbt:dev-UHF-10535
• Run make drush-cr

How to test

• Check that text looks good especially for h1, h2, h3, h4, h5, h6 (easiest to create a page with different headings, body etc)
• Check that code follows our standards

This PR has been checked with a designer and approved by them!

Continuous documentation

• This feature has been documented/the documentation has been updated
• This change doesn't require updates to the documentation

Translations

• Translations have been added to .po -files and included in this PR

[github-actions]

⚠️ Visual regression found! Please check if this change is wanted or accidental. You can check the output here: https://city-of-helsinki.github.io/drupal-hdbt/pull/1122/html_report/

[teroelonen]

This looks very nice 🦖