Add Euler 1 dim step option to shortcuts.py

[aakashnarayan]

No description provided.

[inducer]

Thanks! Could you look into the linter failure?

Also, this is missing documentation and tests. When writing the documentation, it might be good to remind the user that the stability region for forward Euler includes no nonzero part of the imaginary axis, and therefore forward Euler is unstable for DG operators applied to hyperbolic PDEs discretized with central fluxes.

[inducer]

Please add a test and fix the linter. Converting to draft and unsubcribing in the meantime, please request review when ready.