fix(a11y): add wcag-aa color contrast

[userquin]

This PR includes:

• updates utils/severity.ts colors including a darker color for light theme at severity and severity text colors constants
• updates utils/npm/outdated-dependencies.ts colors including a darker color for light theme
• some components to add light and dark theme colors
• badge at app/components/Tag/Static.vue‎ using opacity-40: changed variant ghost to a lighter text color with a dashed border adding a gray solid border to the default
• app/components/Package/VulnerabilityTree.vue using divs inside buttons
• updates server/utils/shiki.ts to replace some red and green colors at github-light theme, we may need to review the the them at shiki

closes #1167