Header or Dashboard

**Is your feature request related to a problem? Please describe.**
Related to Issue #101 **Header should not be visible when logged out.**
Now Header is in the App component, which is shown on every page.

**Describe the solution you'd like**
Two solutions are:
1. Keep it in App.tsx and hide it on some pages such as login, signup
2. Create a new page called Dashboard which works as a console. Projects and the individual project can be imported to this page so that the user can manage them without jumping to another page.

**Short demo**


Start by reading App.tsx and Issue #101, then compare the proposed header behavior with the linked dashboard demo. Clarify whether the intended result is conditional header visibility or a new dashboard page; done should cover the logged-out pages and the project-management flow described in the issue.

Written by the indexing model from the issue text.