Sylvia/docs/sfd

@mhoeber @lamagnifica SFD_ORA.rst and SFD_mathformatting.rst are ready for a dev review when you guys have the time. (SFD_certificates is still in the writing phase, so ignore that one for now.) Thanks!
I meant my suggestion at line 162, about maybe not combining the concept of indicating multiplication explicitly (described here on line 29) with the concept of using parens around a function