Motivation: JSch serves as 'default' implementations of the SSH
transport. If a client application does not use it then there is no need
to pull in this dependency.

Move the classes depending on JSch to an OSGi fragment extending the
org.eclipse.jgit bundle and keep them in the same package as before
since moving them to another package would break API. Defer moving them
to a separate package to the next major release.

Add a new feature org.eclipse.jgit.ssh.jsch feature to enable
installation. With that users can now decide which of the ssh client
integrations (JCraft JSch or Apache Mina SSHD) they want to install.
We will remove the JCraft JSch integration in a later step due to the
reasons discussed in bug 520927.

Bug: 553625
Change-Id: I5979c8a9dbbe878a2e8ac0fbfde7230059d74dc2
Also-by: Michael Dardis <git@md-5.net>
Signed-off-by: Michael Dardis <git@md-5.net>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Signed-off-by: David Ostrovsky <david@ostrovsky.org>

Update target platforms, maven and bazel builds to use sshd 2.2.0.

Adapt internal classes to changed sshd interfaces and remove previous
work-arounds for asking repeatedly for key passwords and for loading
keys lazily; both are now done by sshd.

CQ: 19034
CQ: 19035
Bug: 541425
Change-Id: I85e1df6ebb8a94953a912d9b2b8a7b5bdfbd608a
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

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>

Change-Id: I7eb83e0560b1826c4f8567e9bc5fbdb2ae3fe9d0
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

Add a new ssh client implementation based on Apach MINA sshd 2.0.0.

This implementation uses JGit's own config file parser and host entry
resolver. Code inspection of the Apache MINA implementation revealed
a few bugs or idiosyncrasies that immediately would re-introduce bugs
already fixed in the past in JGit.

Apache MINA sshd is not without quirks either, and I had to configure
and override more than I had expected. But at least it was all doable
in clean ways.

Apache MINA boasts support for Bouncy Castle, so in theory this should
open the way to using more ssh key algorithms, such as ed25519.

The implementation is in a separate bundle and is still not used in
the core org.eclipse.jgit bundle. The tests re-use the ssh tests from
the core test bundle.

Bug: 520927
Change-Id: Ib35e73c35799140fe050d1ff4fb18d0d3596580e
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>