This PR improves the CLI output for `linkerd edges` to reflect the latest API
changes.
Source and destination namespaces for each edge are now shown by default. The
`MSG` column has been replaced with `Secured` and contains a green checkmark or
the reason for no identity. A new `-o wide` flag shows the identity of client
and server if known.
When `linkerd edges` returns JSON, the data will now be sorted alphabetically by
SRC name, meaning edges will be returned in a consistent order. Logic in the CLI
`edges.go` has also been simplified. These changes should result in the Travis
CI builds passing consistently.
Adds an edges command to the CLI. `linkerd edges` displays connections between resources, and Linkerd proxy identities. Currently this feature will only display edges where both the client identity and server identity are known. The next step will be to display edges for which identity is not known and/or one-sided traffic such as Prometheus and tap requests.
Carol A. Scott