Remove Beats central management (#25696)

Remove the Kibana beats central management feature as it has been
replaced by Fleet. Remove xpack command injection and replace with
an includes mod. Restructure the xpack/libbeat/management module
to include all fleet code in the directory (no api or fleet subdirs).

CHANGELOG.next.asciidoc

@@ -32,6 +32,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Update to ECS 1.7.0. {pull}22571[22571]
 - Add support for SCRAM-SHA-512 and SCRAM-SHA-256 in Kafka output. {pull}12867[12867]
 - Remove id_field_data {pull}25239[25239]
+- Removed beats central management {pull}25696[25696], {issue}23908[23908]
 - MacOSX minimum supported version set to 10.14 {issue}24193{24193}
 
 *Auditbeat*

filebeat/docs/howto/load-ingest-pipelines.asciidoc

@@ -3,10 +3,8 @@
 
 The ingest pipelines used to parse log lines are set up automatically the first
 time you run {beatname_uc}, assuming the {es} output is enabled. If you're sending
-events to {ls}, or plan to use
-<<configuration-central-management,{beats} central management>>, you need to
-load the ingest pipelines manually. To do this, run the `setup` command with
-the `--pipelines` option specified. If you used the
+events to {ls} you need to load the ingest pipelines manually. To do this, run the
+`setup` command with the `--pipelines` option specified. If you used the
 <<modules-command,`modules`>> command to enable modules in the `modules.d`
 directory, also specify the `--modules` flag. For example, the following command
 loads the ingest pipelines used by all filesets enabled in the system, nginx,
@@ -44,4 +42,4 @@ PS > .{backslash}{beatname_lc}.exe setup --pipelines --modules system,nginx,mysq
 
 TIP: If you're loading ingest pipelines manually because you want to send events
 to {ls}, also see
-{logstash-ref}/filebeat-modules.html[Working with {beatname_uc} modules].
+{logstash-ref}/filebeat-modules.html[Working with {beatname_uc} modules].

filebeat/docs/index.asciidoc

@@ -49,8 +49,6 @@ include::./configuring-howto.asciidoc[]
 
 include::{docdir}/howto/howto.asciidoc[]
 
-include::{libbeat-dir}/shared-central-management.asciidoc[]
-
 include::./modules.asciidoc[]
 
 include::./fields.asciidoc[]

metricbeat/docs/index.asciidoc

@@ -49,8 +49,6 @@ include::./configuring-howto.asciidoc[]
 
 include::{docdir}/howto/howto.asciidoc[]
 
-include::{libbeat-dir}/shared-central-management.asciidoc[]
-
 include::./modules.asciidoc[]
 
 include::./fields.asciidoc[]

x-pack/auditbeat/cmd/root.go

@@ -7,10 +7,10 @@ package cmd
 import (
 	auditbeatcmd "github.com/elastic/beats/v7/auditbeat/cmd"
 	"github.com/elastic/beats/v7/libbeat/cmd"
-	xpackcmd "github.com/elastic/beats/v7/x-pack/libbeat/cmd"
 
 	// Register Auditbeat x-pack modules.
 	_ "github.com/elastic/beats/v7/x-pack/auditbeat/include"
+	_ "github.com/elastic/beats/v7/x-pack/libbeat/include"
 )
 
 // Name of the beat
@@ -23,5 +23,4 @@ func init() {
 	settings := auditbeatcmd.AuditbeatSettings()
 	settings.ElasticLicensed = true
 	RootCmd = auditbeatcmd.Initialize(settings)
-	xpackcmd.AddXPack(RootCmd, auditbeatcmd.Name)
 }