Update JNA to 4.2.1

It's a follow-up to https://github.com/jenkinsci/jenkins/pull/1861

Fixes the regression on linux-arm: https://github.com/java-native-access/jna/issues/507

[JENKINS-15792] Update jna to 4.2.0

[JENKINS-755] Describe the built-in JDK as '(System)'.

Update login.jelly to avoid autocorrect of username on mobile devices

[JENKINS-31098] Deletage remove a node back to Computer.doDoDelete()

Revert trigger optimisation

Provide a default implementation of Descriptor.getDisplayName

[FIXED JENKINS-31055] Make Node implement Saveable

Trim display name before applying it

The current implementation is not robust against blank display name

Seems rather unlikely, but none the less it is a possibility. Not sure how we should handle this though:

* We do not want to hold the Queue lock while performing I/O as that will grind everything to a halt
* We do not want a big fat lock on all nodes
* If we have a per-node lock then the save everything method may have to grab them all

In short, it gets ugly real fast.

For now, I believe that the risk is very low as releasing a lock does not intrinsically deschedule a currently running thread so the likely course of events is that the thread will release the lock and at least start the save before a competing thread could acquire the lock update remove the node release the lock and delete the node's directory

Use of class Base64 in a static way

- Also tidy up some of the mess logic in both #1866 and #1860

Jenkins.updateNode(): Call getQueue().scheduleMaintenance() to be sure to update builds in the queue with the change done in the node (+  Add since 1.634)

pt_BR translation

Add de translations for TimerTrigger