Switch from CLI + web API to Razor Page web application

[21Philip]

We need a Razor Page web application instead of the old command-line interface and web API.

User story: As a user i want to interact with Chirp through a web page rather than a command-line, in order to fell more comfortable and ease use.

Acceptance criteria:

• [x] Timeline of all cheeps is available under root endpoint (/)
• [x] Timeline of all cheeps written by some user is available under the endpoint /<username>