Fix javadoc errors

[JENKINS-34073] Revert fix for JENKINS-21486

[JENKINS-33364] Core documentation: Freestyle project config

Tested with Java 8 and "mvn javadoc:test-javadoc".  Eliminates errors such as:

    [ERROR] java/hudson/os/DCOMSandbox.java:18: error: bad use of '>'

Eliminates errors with Java 8 and "mvn javadoc:test-javadoc" such as:

    [ERROR] jenkins/core/src/test/java/hudson/os/DCOMSandbox.java:18: error: bad use of '>'

This reverts commit fa39668b, reversing
changes made to be9bc0db.

This reverts commit 0846358b, reversing
changes made to 2c9adc99.

Re-introduce a reference to the setup administrator password in the logs

This makes if possible for users without access to filesystems, like those
running Jenkins masters in Docker containers (unmapped jenkins_home) to still be
able to successfully use Jenkins 2.0

This commit also fixes an errant reference to "security token" which we no
longer use in the beginning of the Getting Started wizard, opting instead for
"administrator password"

[FIXED JENKINS-34035] - honor jenkins.install.runSetupWizard=false

[FIX JENKINS-33942] Fixed NPE when non-exists run requested

[JENKINS-21486] Follow-up

Do not use '_' as an identifier

Display of shortName of disabled plugin is enough. Fix copy-paste error
in the message for disabled dependencies

JENKINS-33930 focus color for delete

style only.

Fix href tags

Eliminates errors with Java 8 and "mvn javadoc:test-javadoc" such as:

    [ERROR] jenkins/core/src/test/java/hudson/model/ItemsTest.java:12: error: unknown attribute: hef
    [ERROR] * @author: <a hef="mailto:nicolas.deloof@gmail.com">Nicolas De Loof</a>

[FIX JENKINS-33805] rename install/upgrade files to be more clear & consistent

[JENKINS-31162] Provide a new Item Category

[FIX JENKINS-33978] Set file permissions on the file before writing the secret

[JENKINS-33800] - fileNotFound exception / more accurately determine if this is an upgrade

Eliminates Java 8 warnings:
  (use of '_' as an identifier might not be supported in releases after Java SE 8)