SSH keys configured in config.sh file are added to config.json, do not replace it

[etcetc]

Currently, the update script explicitly adds any new keys specified in the config.sh file to the os.sshKeys entry of config.json. While it seems this is the desired behavior, it has undesirable effects.

1. It becomes very difficult to keep a reference config.sh for the group of field devices
2. It becomes very difficult to deprecate and replace ssh keys

To reproduce issue:

0. check the config.json file on the target device. Check that the value for key os.sshKeys is empty.
1. Add an ssh key in config.sh script, e.g.
   SSHKEYS=("ssh-rsa AAAA ..... testKey")
2. Configure the key for the test unit in batch
3. run the run.sh script.
4. View the config.json file on the target device. It will now include the specified key
5. Change the key in config.sh
6. Remove config.log and run run.sh again
7. View the config.json file on the target device. It will now include two copies of the specified key

[jellyfish-bot]

[saintaardvark] This issue has attached support thread https://jel.ly.fish/#/728a48e0-84fa-4209-9509-88f613cbafd2

[etcetc]

issue addressed in https://github.com/etcetc/configizer