MMCTL: Add import delete cmd for removing the import files (#29764)

Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>

server/cmd/mmctl/docs/mmctl_import.rst

@@ -37,6 +37,7 @@ SEE ALSO
 ~~~~~~~~
 
 * `mmctl <mmctl.rst>`_ 	 - Remote client for the Open Source, self-hosted Slack-alternative
+* `mmctl import delete <mmctl_import_delete.rst>`_ 	 - Delete an import file
 * `mmctl import job <mmctl_import_job.rst>`_ 	 - List and show import jobs
 * `mmctl import list <mmctl_import_list.rst>`_ 	 - List import files
 * `mmctl import process <mmctl_import_process.rst>`_ 	 - Start an import job

server/cmd/mmctl/docs/mmctl_import_delete.rst

@@ -0,0 +1,51 @@
+.. _mmctl_import_delete:
+
+mmctl import delete
+-------------------
+
+Delete an import file
+
+Synopsis
+~~~~~~~~
+
+
+Delete an import file
+
+::
+
+  mmctl import delete [importname] [flags]
+
+Examples
+~~~~~~~~
+
+::
+
+    import delete import_file.zip
+
+Options
+~~~~~~~
+
+::
+
+  -h, --help   help for delete
+
+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 import <mmctl_import.rst>`_ 	 - Management of imports
+