Documented this feature and integrated a newer version of Stapler.

I took the opportunity to reorder the content in the section, so that
the tree parameter becomes the main subject.

At this point, the depth parameter should be only used in a limited
circumstance, so it should be treated as such.

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>

[FIXED JENKINS-22822] PeepholePermalink should maintain an in-memory cache of symlinks to avoid disk I/O.

[JENKINS-23151] Need to revert part of 5789f0c7 since codemirror-mode on f:textarea apparently does not work for lazy-load fragments.

[FIXED JENKINS-12753] Added PluginStrategy.getShortName to avoid actually trying to unpack a plugin before throwing RestartRequiredException.