Sylvester and Lyapunov equations for octonions

https://pjm.ppu.edu/sites/default/files/papers/PJM_Sep_2016_34.pdf purports to give equations for solutions to Sylvester's equations (with Lyapunov as a special case) for octonions. If they work, we could adapt them here, at least for the scalar case, as in https://github.com/JuliaGeometry/Quaternions.jl/pull/65.