Include the net.i2p.crypto.eddsa bundle via a hard dependency.
Add tests for dealing with ed25519 host keys and user key files.
Manual tests: fetching from git.eclipse.org with an ed25519 user key,
and pushing this change itself using the same ed25519 key.
Note that sshd 2.0.0 does not yet support encrypted ed25519 private
keys.
Bug: 541272
Change-Id: I7072f4014d9eca755b4a2412e19c086235e5eae9
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>