Move every HTML component to the public application

[daleal]

Right now, when requesting for /:username Num directs that request to a Function, that processes the username and returns HTML with the user data. What we should be doing instead is that we should receive every request for /:username on an HTML on the public application. This HTML should have a JavaScript file that makes a request to a Function, which should now return a JSON with the user data (instead of returning the HTML directly). Finally, the JavaScript file should use this information to change the content of the HTML being showed to the user with the data just retrieved.

Caveat: This change by itself would screw our og tags (the preview data), as any crawler would find itself with an empty HTML on its rusty little hands. We would probably need to migrate immediately to a more complete frontend framework that supports SSR.