Show a link to the Phorge homepage

Summary:
It seems we were missing a link to the project homepage.

Also we set the language of the HTML document.

Preview:

Test Plan: Our homepage must be > 0.00001% more cute.

Reviewers: waldyrious, avivey

Reviewed By: waldyrious, avivey

Subscribers: tobiaswiese, Matthew, Cigaryno

Differential Revision: https://we.phorge.it/D25413