[#1639] node: Support active RPC limiting

- Allow configuration of active RPC limits for method groups
- Apply RPC limiting for all services except the control service

Signed-off-by: Aleksey Savchuk <a.savchuk@yadro.com>

docs/storage-node-configuration.md

@@ -416,6 +416,27 @@ object:
 | `delete.tombstone_lifetime` | `int`      | `5`           | Tombstone lifetime for removed objects in epochs.                                              |
 | `get.priority`              | `[]string` |               | List of metrics of nodes for prioritization. Used for computing response on GET requests.      |
 
+
+# `rpc` section
+Contains limits on the number of active RPC for specified method(s).
+
+```yaml
+rpc:
+  limits:
+    - methods:
+      - /neo.fs.v2.object.ObjectService/PutSingle
+      - /neo.fs.v2.object.ObjectService/Put
+      max_ops: 1000
+    - methods:
+      - /neo.fs.v2.object.ObjectService/Get
+      max_ops: 10000
+```
+
+| Parameter        | Type       | Default value | Description                                                  |
+|------------------|------------|---------------|--------------------------------------------------------------|
+| `limits.max_ops` | `int`      |               | Maximum number of active RPC allowed for the given method(s) |
+| `limits.methods` | `[]string` |               | List of RPC methods sharing the given limit                  |
+
 # `runtime` section
 Contains runtime parameters.