Allow Companion app to connect to Confluence without requiring infrastructure changes

Some of our customers are facing an issue where they cannot use the Companion App to edit files. They run Confluence in managed environments where proxies are employed and ports are often blocked. Their infrastructure teams may also have security protocols or policies they must abide by that forbid some of the access that Companion App requires to function.

This access is often something both the users and the infrastructure teams have no ability to change in their environment leading to an impaired experience and no ability to edit documents in this manner.

Since most browsers do not allow an insecure websocket connection (from the browser to Companion) when Confluence is hosted on a secure connection, in order to make a secure websocket connection between the browser and companion, we've created a DNS on the public internet for atlassian-domain-for-localhost-connections-only.com that maps to the IP address 127.0.0.1. It is imperative that this domain is excluded from the Browser's forward proxies, otherwise the Browser will never find its way from the forward proxy back to the Companion App on the local machine. If the connection is not allowed we do fall back to trying to connect to 127.0.0.1 directly if the domain connections failed, however depending on the cause of failure this could take additional time before a connection is made.