Khepri: Clean up the proxy functions of the integration code

[Why]
The `rabbit_khepri` module grew during the work to add Khepri support to
RabbitMQ and while Khepri was itself written. The current code is
therefore unorganized.

[How]
This commit tries to change proxy functions to be close to their Khepri
equivalent.

The module continues to set non-default options for write functions. We
also add the variants that take an option map to be consistent and not
have to deal with that in the future.

Several legacy functions were removed, either because they were no
longer called or because they were replace by a regular Khepri call.

Author: dumbbell

deps/rabbit/src/rabbit_db.erl

@@ -328,7 +328,7 @@ list_in_khepri(Path) ->
       Objects :: [term()].
 
 list_in_khepri(Path, Options) ->
-    case rabbit_khepri:match(Path, Options) of
+    case rabbit_khepri:get_many(Path, Options) of
         {ok, Map} -> maps:values(Map);
         _         -> []
     end.

deps/rabbit/src/rabbit_db_rtparams.erl

@@ -357,7 +357,7 @@ delete_vhost_in_mnesia_tx(VHostName) ->
 delete_vhost_in_khepri(VHostName) ->
     Pattern = khepri_vhost_rp_path(
                 VHostName, ?KHEPRI_WILDCARD_STAR, ?KHEPRI_WILDCARD_STAR),
-    case rabbit_khepri:adv_delete_many(Pattern) of
+    case rabbit_khepri:adv_delete(Pattern) of
         {ok, NodePropsMap} ->
             RTParams =
             maps:fold(

deps/rabbit/src/rabbit_db_user.erl

@@ -402,7 +402,7 @@ match_user_permissions_in_mnesia_tx(Username, VHostName) ->
 
 match_user_permissions_in_khepri('_' = _Username, '_' = _VHostName) ->
     Path = khepri_user_permission_path(?KHEPRI_WILDCARD_STAR, ?KHEPRI_WILDCARD_STAR),
-    case rabbit_khepri:match(Path) of
+    case rabbit_khepri:get_many(Path) of
         {ok, Map} ->
             maps:values(Map);
         _ ->