Tell Teatro to npm + bower install separately

Bower on Teatro needs `--allow-root` flag.

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Remove Lato fonts

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Use Fira Sans as OpenProject standard typeface

Loaded from Mozilla CDN for the time-being.

User Story # 17605

Signed-off-by: Alex Coles <alex@alexbcoles.com>