Introduce output json to eos_config

[ryanmerolle]

SUMMARY

It would be useful to natively use ansible when backing up or applying config, for the show running-config via the json format.

ISSUE TYPE

• Feature Idea

COMPONENT NAME

eos_config

ADDITIONAL INFORMATION

- name: backup config in json format
  arista.eos.eos_config:
    backup: yes
    output: json
    backup_options:
      filename: backup.json
      dir_path: /home/user