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.
Jay Modi
javanna
David Pilato