Remove any ESS related references

[ppapapetrou76]

We need to remove any references to ESS - The following have been identified. It's a good idea to do a quick pass

1. In init command: “Enter the URL of the Elastic Cloud API or your ECE installation:”
2. ecctl help command: --host string : Base URL to use (default "https://api.elastic-cloud.com") should remove the default, ask for an ecctl init, or proper ECE host if one doesn’t exist.
3. Drop referencing regions, as they are ESS specific
4. Remove --region flag, and config file region reference

[marclop]

#50 resolves all points except 1. Will fix it in an upcoming PR since the current seems a bit out of band