[MS1] Revamp release process #1

[ppkarwasz]

The current release process is still very time consuming and requires a lot of technical skills, patience and a UNIX-like OS to be performed. Out of the 17 PMC members in Apache Logging Services, only 2 have done a release of Log4j 2.x.

We aim at providing a release process that is:

• fast: it doesn't take several days to perform a release,
• reliable: the release manager should not slalom between failing tests to perform the release,
• automated: the release should be possible to perform without access to a developer desktop, if it is necessary.

This task is divided into:

• Create a reusable release process #1772
• Move Log4j JMX GUI to its own repository #1773
• Use the release process on secondary repositories #1774
• Stabilize Log4j tests #1776
• Align support files #1775