adding some TODO comments

the @~2 commit is cherry-picked from beekeeper's repo. it addes declaration of dynamic_domains feature support to some modules. to see the full list of the changed modules use this command:
   git show --name-only  --pretty="format:" @~2 | sed -r "s_.*/(.*)\.erl_\1_p;d" | sort

the conversion of 'mod_commands' and 'mod_muc_light_commands' modules seems to be done, however there's no integration testing enabled for that modules in dynamic_domains.spec

other modules are dynamically initialised during the execution of the tests currently configured in dynamic_domains.spec, however there's no waranty that all of them are fully converted and tested. here is the list of that modules:
 * mod_mam
 * mod_mam_cache_user
 * mod_mam_meta
 * mod_mam_mnesia_prefs
 * mod_mam_muc
 * mod_mam_muc_cache_user
 * mod_mam_muc_rdbms_arch
 * mod_mam_muc_rdbms_async_pool_writer
 * mod_mam_rdbms_arch
 * mod_mam_rdbms_async_pool_writer
 * mod_mam_rdbms_prefs
 * mod_mam_rdbms_user
 * mod_muc
 * mod_muc_light
 * mod_muc_log

src/mod_commands.erl

@@ -45,6 +45,9 @@ stop(_) -> stop().
 
 -spec supported_features() -> [atom()].
 supported_features() ->
+    %% TODO: this module should be reworked into service
+    %% from the quick look it seems that the conversion for dynamic domains is done,
+    %% but there's no testing for this module enabled at dynamic_domains.spec yet.
     [dynamic_domains].
 
 %%%