[Website] Get started page URL parameters not reset

[ChaiBapchya]

Description

Get started page has a nice approach for getting platform & use-case specific instructions.
URL update doesn't reset device parameter when OS Platform config is switched from Devices to other options [say Windows/Mac/Linux].

Problem

There are 5 potential arguments appended to the url
https://mxnet.incubator.apache.org/versions/1.6/get_started?platform=<>&language=<>&processor=<>&environ=<>&iot=<>&

platform=
iot=
language=
processor=
environ=

However, iot parameter is specific to platform=devices & hence should be reset when platform!=devices

Similarly, there are other places, where arguments should be reset but they continue to have previous values unless overriden by the selection
E.g. https://mxnet.incubator.apache.org/versions/1.6/get_started?platform=macos&language=scala&processor=cpu&environ=build-from-source&iot=raspberry-pi&

While this still gives the correct suggestion but the URL doesn't read correctly.

Steps to reproduce

1. Get started page URL: https://mxnet.incubator.apache.org/versions/1.6/get_started?
2. Upon selecting OS/Platform as Devices & Device as Nvidia Jetson: URL becomes
   https://mxnet.incubator.apache.org/versions/1.6/get_started?platform=devices&iot=nvidia-jetson&

So far so good.

3. Switching OS/Platform to anything else doesn't reset iot parameter.
   For e.g. Switching platform to Windows doesn't reset iot anymore.
   https://mxnet.incubator.apache.org/versions/1.6/get_started?platform=windows&iot=nvidia-jetson&

4. Despite selecting language, GPU & distribution
   https://mxnet.incubator.apache.org/versions/1.6/get_started?platform=windows&language=python&processor=cpu&environ=pip&iot=nvidia-jetson&

iot parameter still remains set.

Ideally it shouldn't have iot param in the url.

[ChaiBapchya]

@ys2843

[ChaiBapchya]

@mxnet-label-bot update [bug, website]