Create Design for User-Secrets Page

Create Design for User-Secrets Page in Account Settings.

There are initial design in PRD and figma, but it should be finalized.
https://www.notion.so/coderhq/Secrets-Builtin-1edd579be59280f58cd9df010b42e905?source=copy_link#1f3d579be59280f48bbbf3deaae1649d

- [ ] UI Page for creation of secret
- [ ] UI Page for listing of secrets
- [ ] UI Flow for updating of secrets value and/or metadata