clean branch for colour theme / typography

Notion ticket link

Set Up Color Theme

Implementation description

• created theme directory
• access colours like blue.700, or, if there's no shade do white.default
• look at CreatePasswordPage.tsx for example
• text styles are used just like before

Steps to test

1. you can open create password page to see that the colours work

What should reviewers focus on?

• CreatePasswordPage for example
• frontend/src/theme/colors

Checklist

• My PR name is descriptive and in imperative tense
• My commit messages are descriptive and in imperative tense. My commits are atomic and trivial commits are squashed or fixup'd into non-trivial commits
• I have run the appropriate linter(s)
• I have requested a review from the PL, as well as other devs who have background knowledge on this PR or who will be building on top of this PR