Bring back support for GraphiQL

[manasag]

In order to make graphqurl work with later versions of nodejs (v22), we have to remove support for GraphiQL. The customised GraphiQL code in this project is very old, and it's probably impossible at this stage to make it compatible with node v22 with just packaging updates. Hence in order to unblock the primary users of graphqurl which use this as a CLI tool or a library, GraphiQL support have been removed v2.0.0 onward.

This issue is to bring back the GraphiQL support. Probably we should try integrating the new GraphiQL 2.0 for this.
This is the issue which resulted in GraphiQL being removed.