Make nodeOperators a JSON instead of md

[PeterBenc]

Issue To Be Solved

Currently, we fetch names of node operators from here, https://github.com/onflow/flow/blob/master/nodeoperators/NodeOperatorList.md
The issue is that this list is a .md file. We currently parse the .md but recently it changed which broke the parsing.
The current version creates technical dept and maintenance costs for anybody who wants to use this data.

(Optional): Suggest A Solution

Create a JSON file that would contain node ids and validator names. This new JSON file would replace the list of node operators in the md file.

Alternatively, node operator names can be added to this file https://github.com/onflow/flow/blob/master/nodeoperators/nodelist.json