Summary

Followin up from PLANET-5954, as we decided what we want to do, it's time to apply these rules initially to the theme.

Requirements

• Adjust phpcs and relevant config file in repo based on the ADR.
• Make relevant code changes across our php code, so that linting tests pass again.

Resources

• PHP coding standards ADR
• Standard decision matrix
• Controlshift plugin repo where these changes are already implemented.