This removes the need for go-cmp, which is extremely bloaty so we had
to leave it out of iOS. As a result, we had also left it out of macOS,
and so we didn't print netmap diffs at all on darwin-based platforms.
Oops.
As a bonus, the output format of the new function is way better.
Minor oddity: because I used the dumbest possible diff algorithm, the
sort order is a bit dumb. We print all "removed" lines and then print
all "added" lines, rather than doing the usual diff-like thing of
interspersing them. This probably doesn't matter (maybe it's an
improvement).
The .Concise() view had grown hard to read over time. Originally, we
assumed a peer almost always had just one endpoint and one-or-more
allowedips. With magicsock, we now almost always have multiple
endpoints per peer. And empirically, almost every peer has only one
allowedip.
Change their order so we can line up allowedips vertically. Also do
some tweaking to make multiple endpoints easier to read.
While we're here, add a column to show the home DERP server of each
peer, if any.
We still include them directly in the controlclient network map
just where we have been. Client plumbing we can do later.
Signed-off-by: David Crawshaw <crawshaw@tailscale.com>