Update default PrimeNG theme

Stork UI is currently using legacy Nova theme, which was a default showcase theme for PrimeNG v9 (we are using latest major v17 PrimeNG, so we are 8 major releases back with the theme).

After that PrimeNG introduced default themes in showcase app and in the documentation:

• saga (v10-v12)
• lara (v13-v17.12)
• aura (current v17)

We could consider updating the theme to more recent lara or aura for couple of reasons:

• fresh and up to date look and feel
• better theme compatibility with latest PrimeNG code changes
• more recent styling fixes
• easy to implement light/dark mode switch

It could also improve our frontend code quality:

• get rid of unnecessary styling workarounds (probably they were fixed in new themes)
• get rid of hardcoded colors, styles etc. and use theme variables
• get rid of hardcoded style="" attributes

Example screens with lara theme applied:

Dark mode