Most of the time we don't care about the return values of a print
function, but we should at leased visualize that there is a return
value that we don't care about or want to ignore with a "_".
The execution was originaly build to be used as a lib, but this is no
longer the case and so I removed all the `io.Writer` and `io.Reader`
interactions. The app reads now from Stdin and writes to Stdout as it
did before.
It also redoes the error handling so that all errors that are not
treated are being handled in the `main` function.
This is to remove the directory that is used in cobra setups.
While we could kept the file inside the root directory but it only
contains two small functions that can be moved into the `main.go` file.
This reduces the package size by ca. 50%. One draw back of this
change is that there is no longer support for the `config.yml` file.
There is also a change inside the env vars naming: The variables have to
start with `RCON_CLI`.