[JENKINS-10547, JENKINS-22685] Update windows-slave-installer dependency to 1.5

Jenkins issues: JENKINS-10547, JENKINS-22685

Changes in winsw:
* https://github.com/kohsuke/winsw/issues?q=milestone%3Awinsw-1.17
* kohsuke/winsw@2bf9e85

Changes in the module:
* https://github.com/jenkinsci/windows-slave-installer-module/commit/a4d2121812fe9fe1b38bbe9d2cb57b9cd5435a0d
* https://github.com/jenkinsci/windows-slave-installer-module/commit/3fbc8434aba05d5d36f52f345d9d0176e98459be

Improve readability of Jenkins.getTarget()

[JENKINS-30395] Occasional ClosedByInterruptException

The ~dozen inlined options and braceless conditional weren't the easiest
to read, especially with the one compound statement in there. Took me a
minute to convince myself that operator precedence & associativity
really made that work as intended.

I *think* those strings could drop their slashes and be combined with
the other loop (e.g. go over
Sets.concat(ALWAYS_READABLE_PATHS, getUnprotectedRootActions()), but
without spending more time confirming that, I'm leaving the behavior
exactly the same as it was before.

[JENKINS-30139] Switch from a big fat lock to a concurrent collection

[JENKINS-30374] Update obsolete help message

Remove obsolete reference to "location you configured above" since the location is now determined automatically rather than explicitly configured.

Use slf4j adapters for logging.

 By means of this *all* logging should go to JUL.  By defining slf4j-api as compile
 scope we mark it as the one to be used, while by declaring it optional we make
 sure it is not packaged in the resulting HPI.

Document allBuilds for Job remote access API

- By introducing adapters for log4j and commons-logging and
- including the original log4j and commons-logging dependencies as provided
all logging should be redirected to slf4j and finally java.util.logging.

[JENKINS-28440] Additional fixes for #1715