Number cell input's step can be set using metadata

[kgoo124]

Currently, the number cell editor automatically uses step of 'any'. This results in the step for a decimal number always being 1. I figured I would try to tackle this problem at the source.

This PR allows a step to be passed into the metadata for a cell. If no step is found, it will default to any.

@lmcnichols @ryuntalan

[kgoo124]

We could also get smarter and have the NumberCellEditor calculate what the step is based on how many decimal places are in the current value.

Example:
10.23 => 2 decimal places, step = "0.01"