[ENHANCEMENT] Update dediscretize to support user defined sampling (not just uniform) from a parameters bin

### Relation

The function, `dediscretize` samples a value within the inputted parameters bin and currently enforces uniform sampling within a bin. This function is called by `dbn_hierarchical_sample` to create values based on the sampled parameter bin. For example when using the uncorrelated conventional aircraft encounter models, such as `uncor_1200only_fwse_v1p2`, if the altitude layer (L) parameter bin is 1, then `dediscretize` will sample a value from the 1st altitude bin. Currently the first altitude bin is [50, 500) feet AGL, so `dediscretize` will uniformly sample a value, `U(50, 500]`

### Description

Update `dediscretize` to enable non-uniform sampling within a bin. A good first start would be implementing a Gaussian sampling option, followed by functionality to enable the user to input their own sampling function.

### Additional

`dediscretize` is called by lines 25 – 37 in `dbn_hierarchical_sample.m`. Lines 25-31 is for the sample from the initial network while lines 33 – 37 are the events (i.e., for the uncorrelated conventional aircraft models: vertical rate, turn rate, acceleration) for each timestep.

This issue will also be heavily reviewed by the airspace encounter models team. It is important that the models not be misused to sample and create tracks, and subsequently encounters, that intentionally skew the encounter geometry to be easier for a collision avoidance system to resolve.