Fluid: Initial support for 2D fluid simulations

Initial adjustments for 2D (real-time) simulations.

Basic functionality includes:
- 2D/3D switcher in domain settings
- 2D simulation support for smoke/fire, wavelet noise, liquid
particles, secondary particles
- UI switcher to choose the axis that will be simulated on
- Planar visualization in workbench render

Some things that remain to do (non-exhaustive list):
- Eevee & Cycles support
- Liquid meshing
- Liquid viscosity solver

Fluid: Removed noise resolution field in domain settings

There is no need to keep have noise resolution in the domain settings.

Resolutions are stored in the fluid object which also handles memory
of grids.