[DOCS] Create install-upgrade folder (#196)

Author: lcawl

docs/index.asciidoc renamed to docs/en/install-upgrade/index.asciidoc

@@ -1,8 +1,8 @@
 [[elastic-stack]]
 = Installation and Upgrade Guide
 
-:es-repo-dir:        {docdir}/../../elasticsearch/docs
-:kib-repo-dir:       {docdir}/../../kibana/docs
+:es-repo-dir:        {docdir}/../../../../elasticsearch/docs
+:kib-repo-dir:       {docdir}/../../../../kibana/docs
 
 include::{asciidoc-dir}/../../shared/attributes.asciidoc[]
 include::{es-repo-dir}/Versions.asciidoc[]
@@ -34,4 +34,4 @@ include::installing-stack.asciidoc[]
 
 include::upgrading-stack.asciidoc[]
 
-include::en/install-upgrade/breaking.asciidoc[]
+include::breaking.asciidoc[]