Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/scripts/setup_go_work.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+if [[ $1 != "true" ]] ;
+then
+    echo "Creating a go.work file"
+
+    txt="go 1.19\n\nuse ./\n"
+    
+    if [ "$BUILD_ENTERPRISE_READY" == "true" ] 
+    then
+        txt="${txt}use ../enterprise\n"
+    fi
+    
+    if [ "$BUILD_PLAYBOOKS" == "true" ]
+    then
+        txt="${txt}use ../mattermost-plugin-playbooks\n"
+    fi
+
+    printf "$txt" > "../go.work"
+fi