Implement FDAlgorithm parameter getters

[Mstrutov]

Frontend side needs information about available parameters, e.g. maxLHS, error, seed, etc. Therefore we need a method in base class FDAlgorithm that would concurrently output info in a form similar to: "{: }".

An example:

{
  "seed": {
    "min": 0,
    "type": "int"
  },
  "error": {
    "min": 0,
    "max": 1,
    "type": "double"
  }
  ...
}

Synchronize the API with frontend developers.