Check if number of timesteps is sufficient

[torbjornstoro]

Feature

Desired Behavior / Functionality

Run simulation long enough for steady state

What Needs to Be Done

• Let the users specify timesteps but then give some explanation how to choose in the documentation
• Come up with some code based on WL, dt, CFL etc. to check if the chosen timestep is sensible

How Can It Be Tested

Run with wrong timestep :)

[torbjornstoro]

Higher timesteps is required for higher wavelengths

[gomezzz]

Ideally, start with implementig a stupid check like period / total time > something... and if not throw a warning

[gomezzz]

I think this is implemented now, if not feel free to reopen