We had this as a dependency for legacy dependencies that still needed
the Log4j 1.2 API. This appears to no longer be necessary, so this
commit removes this artifact as a dependency.
To remove this dependency, we had to fix a few places where we were
accidentally relying on Log4j 1.2 instead of Log4j 2 (easy to do, since
both APIs were on the compile-time classpath).
Finally, we can remove our custom Netty logger factory. This was needed
when we were on Log4j 1.2 and handled logging in our own unique
way. When we migrated to Log4j 2 we could have dropped this
dependency. However, even then Netty would still pick up Log4j 1.2 since
it was on the classpath, thus the advantage to removing this as a
dependency now.
This change updates our version of httpclient to version 4.5.8, which
contains the fix for HTTPCLIENT-1968, which is a bug where the client
started re-writing paths that contained encoded reserved characters
with their unreserved form.
The apache commons http client implementations recently released
versions that solve TLS compatibility issues with the new TLS engine
that supports TLSv1.3 with JDK 11. This change updates our code to
use these versions since JDK 11 is a supported JDK and we should
allow the use of TLSv1.3.
As discussed at https://github.com/elastic/elasticsearch-cloud-azure/issues/91#issuecomment-229113595, we know that the current `discovery-azure` plugin only works with Azure Classic VMs / Services (which is somehow Legacy now).
The proposal here is to rename `discovery-azure` to `discovery-azure-classic` in case some users are using it.
And deprecate it for 5.0.
Closes#19144.