Clean up code and remove duplication

[advaith1]

Main

• [ ] Don't duplicate CSS across themes
• [x] Do checks before making Discord API request

Route-specific reused code

Check when re-used code has been moved to functions/vars for the following routes. This also includes other relevant code cleanup/refactoring.

• [x] authentication.ts
• [ ] autosync.ts
• [ ] bots.ts
• [ ] index.ts
• [ ] search.ts
• [ ] servers.ts
• [ ] staff.ts
• [ ] templates.ts
• [ ] users.ts

[carolinaisslaying]

4c3358c begins the improvement of code and duplication in servers.ts