Add Homestead plugin (#3712)

plugins/homestead/homestead.plugin.zsh

+# Homestead basic command completion
+_homestead_get_command_list () {
+  homestead --no-ansi | sed "1,/Available commands/d" | awk '/^ +[a-z]+/ { print $1 }'
+}
+
+_homestead () {
+  compadd `_homestead_get_command_list`
+}
+
+compdef _homestead homestead