Enhancement: Support nested interactive parameters

Currently the getParameterDefinitions() function accepts 4 types: float, int, text, and choice

I am proposing a fifth type that would allow for nesting / grouping of parameters.

This would be useful for scripts which have multiple independent pieces with their own parameters.

Here is an example of how I would picture it being used:

{
  name: 'chassisBolt',     // a javacsript object will be created, filled with its own parameters
  type: 'parameterGroup',  // not sure best name for param type, other ideas include 'object', 'group', 'grouping'
  caption: 'Chassis Bolt', // optional, displayed as a heading above its own parameter list
                           // if omitted, the 'name' is displayed (i.e. 'chassisBolt')
  parameters: { // params go here in the same manner as at the 'top level', including possibly more parameter groups
      {  name: 'headDiameter',  type: 'float', initial: 6, caption: 'Head Diameter:' }
      {  name: 'shankDiameter',  type: 'float', initial: 3, caption: 'Shank Diameter:' }
      {  name: 'length',  type: 'float', initial: 20, caption: 'Length:' }
  }
}

When a parameter group is defined the interactive parameter window should generate a bold heading with the given caption or name, and list all contained parameters beneath it, indented some amount.

Then if I have a function that only needs the bolt related parameters I can pass in params.chassisBolt object and leave out all the other unrelated parameters.

Start by locating getParameterDefinitions() and the code that generates the interactive parameter window. Trace how the existing float, int, text, and choice types are represented and rendered, then define the nested group behavior, including headings, indentation, recursive groups, and the params.chassisBolt object shape. Done means grouped parameters render correctly and nested values are passed to the script as described.