Archive `logging-log4j-boot`

[Volkan Yazıcı]

`logging-log4j-boot` <https://github.com/apache/logging-log4j-boot>, last
touched 6 years ago, is a spin-off from LOG4J2-1775
<https://issues.apache.org/jira/browse/LOG4J2-1775>, where it is stated
that *"The Log4j Boot concept can be superseded by the increased
modularization being done in 3.0. No longer relevant."* I want to archive
this repository. Objections?