feat(observer_cli): Add observer_cli

rebar.config

@@ -50,6 +50,7 @@
     , {emqtt, {git, "https://github.com/emqx/emqtt", {tag, "1.2.3"}}}
     , {rulesql, {git, "https://github.com/emqx/rulesql", {tag, "0.1.2"}}}
     , {recon, {git, "https://github.com/ferd/recon", {tag, "2.5.1"}}}
+    , {observer_cli, "1.6.1"} % NOTE: depends on recon 2.5.1
     , {getopt, "1.0.1"}
     ]}.
 

rebar.config.erl

@@ -226,6 +226,7 @@ relx_apps(ReleaseType) ->
     , {mnesia, load}
     , {ekka, load}
     , {emqx_plugin_libs, load}
+    , observer_cli
     ]
     ++ [emqx_modules || not is_enterprise()]
     ++ [emqx_license || is_enterprise()]