[DOCS][Backport][9.0] Reference cleanup (#124720)

* Fix external URI images (#124350)

* [DOCS] Plugin management reference cleanup (#124578)

* add content to plugin management

* add content to Plugin Management

* Update docs/reference/elasticsearch-plugins/plugin-management.md

Co-authored-by: florent-leborgne <[email protected]>

* fix applies-to tag

* add ech to docset.yml

---------

Co-authored-by: florent-leborgne <[email protected]>

---------

Co-authored-by: florent-leborgne <[email protected]>

Author: charlotte-hoblik

docs/docset.yml

@@ -168,6 +168,7 @@ subs:
   ess:   "Elasticsearch Service"
   ece:   "Elastic Cloud Enterprise"
   eck:   "Elastic Cloud on Kubernetes"
+  ech:   "Elastic Cloud Hosted"
   serverless-full:   "Elastic Cloud Serverless"
   serverless-short:   "Serverless"
   es-serverless:   "Elasticsearch Serverless"

docs/images/exponential-decay-keyword-exp-1.png

@@ -1,6 +1,9 @@
 ---
 mapped_pages:
   - https://www.elastic.co/guide/en/elasticsearch/plugins/current/_other_command_line_parameters.html
+applies_to:
+  deployment:
+    self: ga
 ---
 
 # Other command line parameters [_other_command_line_parameters]

docs/images/exponential-decay-keyword-exp-2.png

@@ -1,6 +1,9 @@
 ---
 mapped_pages:
   - https://www.elastic.co/guide/en/elasticsearch/plugins/current/_plugins_directory.html
+applies_to:
+  deployment:
+    self: ga
 ---
 
 # Plugins directory [_plugins_directory]