cli/self: Stop printing information about the node

To get to a point of separating the users' identity from the node, then the `rad
self` command should not display information related to the node so prominently.

The relation between `rad` and `radicle-node` is really similar to that between
`rad` and SSH Agent. They communicate via socket. So, when this connection is
successful, it is printed, but not more.

There may be some re-learning for users here, but it is worth the improvement.

Note that the information being removed here is available via `rad node status`
(see previous commit).

rad.1.adoc

@@ -115,7 +115,7 @@ For example, to connect to a community node, you can run:
 
 The argument given to *connect* is called a node _address_. It is composed of
 a Node ID (NID), followed by an *@* symbol, and the _host_ name and _port_.
-You can display your NID with *rad self --nid*.
+You can display your NID with *rad node status*.
 
 To make these connections permanent, such that they are always tried on
 startup, add the addresses to your configuration file at