This PR also fixes issues related to
- Add proper newline for `mc admin config get` output
for more than one targets
- Fixes issue of temporary user credentials to have
consistent output
- Fixes a crash when setting a key with empty values
- Fixes a parsing issue with `mc admin config history`
- Fixes gateway ENV handling for etcd server and gateway
This PR brings support for `history` list to
list in the following agreed format
```
~ mc admin config history list -n 2 myminio
RestoreId: df0ebb1e-69b0-4043-b9dd-ab54508f2897
Date: Mon, 04 Nov 2019 17:27:27 GMT
region name="us-east-1" state="on"
region name="us-east-1" state="on"
region name="us-east-1" state="on"
region name="us-east-1" state="on"
RestoreId: ecc6873a-0ed3-41f9-b03e-a2a1bab48b5f
Date: Mon, 04 Nov 2019 17:28:23 GMT
region name=us-east-1 state=off
```
This PR also moves the help templating and coloring to
fully `mc` side instead than `madmin` API.
Harshavardhana