Merge Elasticsearch ingest pipelines pages (#1329)

This removes the Serverless version of the "Elasticsearch ingest
pipelines" page, since it was missing content included in the
non-Serverless version (curl commands, etc.) which are actually
applicable in both environments. So we'll have just [this one
version](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/1329/manage-data/ingest/transform-enrich/ingest-pipelines)
of the page.

@colleenmcginnis and @wajihaparvez, this was part of our IA project so I
hope you don't mind being reviewers. :-)

Author: kilfoyle

manage-data/ingest/transform-enrich/ingest-pipelines-serverless.md

@@ -3,6 +3,7 @@ mapped_pages:
   - https://www.elastic.co/guide/en/elasticsearch/reference/current/ingest.html
 applies_to:
   stack: ga
+  serverless: ga
 ---
 
 # Elasticsearch ingest pipelines [ingest]
@@ -17,10 +18,6 @@ A pipeline consists of a series of configurable tasks called [processors](elasti
 
 You can create and manage ingest pipelines using {{kib}}'s **Ingest Pipelines** feature or the [ingest APIs](https://www.elastic.co/docs/api/doc/elasticsearch/group/endpoint-ingest). {{es}} stores pipelines in the [cluster state](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-cluster-state).
 
-:::{note}
-To run an {{es}} pipeline in {{serverless-full}}, refer to [{{es}} Ingest pipelines (Serverless)](./ingest-pipelines-serverless.md).
-:::
-
 ## Prerequisites [ingest-prerequisites]
 
 * Nodes with the [`ingest`](../../../deploy-manage/distributed-architecture/clusters-nodes-shards/node-roles.md#node-ingest-node) node role handle pipeline processing. To use ingest pipelines, your cluster must have at least one node with the `ingest` role. For heavy ingest loads, we recommend creating [dedicated ingest nodes](../../../deploy-manage/distributed-architecture/clusters-nodes-shards/node-roles.md#node-ingest-node).

manage-data/ingest/transform-enrich/ingest-pipelines.md

@@ -95,7 +95,6 @@ toc:
       - file: ingest/upload-data-files.md
       - file: ingest/transform-enrich.md
         children:
-          - file: ingest/transform-enrich/ingest-pipelines-serverless.md
           - file: ingest/transform-enrich/ingest-pipelines.md
             children:
               - file: ingest/transform-enrich/example-parse-logs.md