[MM-54852] Add mmctl command to download Support Packet (#25419)

* Add mmctl command to download Support Packet

* Simplify file name

* Revert "Simplify file name"

This reverts commit 17084a3350605134ba338ffa25ce43a7c9482f1d.

* Fix docs

server/cmd/mmctl/docs/mmctl_system.rst

@@ -41,5 +41,6 @@ SEE ALSO
 * `mmctl system getbusy <mmctl_system_getbusy.rst>`_ 	 - Get the current busy state
 * `mmctl system setbusy <mmctl_system_setbusy.rst>`_ 	 - Set the busy state to true
 * `mmctl system status <mmctl_system_status.rst>`_ 	 - Prints the status of the server
+* `mmctl system supportpacket <mmctl_system_supportpacket.rst>`_ 	 - Download a Support Packet
 * `mmctl system version <mmctl_system_version.rst>`_ 	 - Prints the remote server version
 

server/cmd/mmctl/docs/mmctl_system_supportpacket.rst

@@ -0,0 +1,52 @@
+.. _mmctl_system_supportpacket:
+
+mmctl system supportpacket
+--------------------------
+
+Download a Support Packet
+
+Synopsis
+~~~~~~~~
+
+
+Generate and download a Support Packet of the server to share it with Mattermost Support
+
+::
+
+  mmctl system supportpacket [flags]
+
+Examples
+~~~~~~~~
+
+::
+
+    system supportpacket
+
+Options
+~~~~~~~
+
+::
+
+  -h, --help                 help for supportpacket
+  -o, --output-file string   Output file name (default "mattermost_support_packet_YYYY-MM-DD-HH-MM.zip")
+
+Options inherited from parent commands
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+      --config string                path to the configuration file (default "$XDG_CONFIG_HOME/mmctl/config")
+      --disable-pager                disables paged output
+      --insecure-sha1-intermediate   allows to use insecure TLS protocols, such as SHA-1
+      --insecure-tls-version         allows to use TLS versions 1.0 and 1.1
+      --json                         the output format will be in json format
+      --local                        allows communicating with the server through a unix socket
+      --quiet                        prevent mmctl to generate output for the commands
+      --strict                       will only run commands if the mmctl version matches the server one
+      --suppress-warnings            disables printing warning messages
+
+SEE ALSO
+~~~~~~~~
+
+* `mmctl system <mmctl_system.rst>`_ 	 - System management
+