Adding a favicon

Summary:

Test Plan: psyduck

Reviewers: adam, alex, anders, ankur, arthur, chase, dolphinigle, jvictor, manu, marko, mom, nika, nikita, pieguy, rumen

CC: engineering

Maniphest Tasks:
changed console background;

Conflicts:
	frontend/static/css/bootstrap.css
changed console background;

Conflicts:
	frontend/static/css/bootstrap.css
Adding background

Summary:

Test Plan: psyduck

Reviewers: adam, alex, anders, ankur, arthur, chase, dolphinigle, jvictor, manu, marko, mom, nika, nikita, pieguy, rumen

CC: engineering

Maniphest Tasks:
This is a step towards prettier demo

Summary:

Test Plan: psyduck

Reviewers: adam, alex, anders, ankur, arthur, chase, dolphinigle, jvictor, manu, marko, mom, nika, nikita, pieguy, rumen

CC: engineering

Maniphest Tasks: