Cleanup custom styling in single-file components

[outdooracorn]

• Add scoped attribute to <style> tags in single-file components
• Use Vuetify-native classes instead of custom styling in Complaint.vue and Interval.vue
• Remove empty <style> tags in single-file components

[github-actions]

Deployment previews on netlify for branch refs/pull/1118/merge will be at the following locations (when build is done):

• UI with mock store: https://b7f5666c07-mock--wbstack-ui.netlify.app/
• UI pointing to prod: https://b7f5666c07-prod--wbstack-ui.netlify.app/

[dati18]

I found one more empty <style> here:
https://github.com/wbstack/ui/blob/main/src/components/Pages/ManageWiki/Cards/Skin.vue