add acceptance filter configuration helpers

Adds helper API functions for configuring CAN controller hardware
acceptance filters.

README.md

@@ -206,10 +206,29 @@ else
 }
 ```
 
+A simple API for generating CAN hardware acceptance filter configurations is also provided.
+Acceptance filters are generated in an extended 29-bit ID + mask scheme and can be used to minimize the number of irrelevant transfers processed in software.
+
+```c
+// Generate an acceptance filter to receive only uavcan.node.Heartbeat.1.0 messages (fixed port ID 7509):
+CanardAcceptanceFilterConfig heartbeat_config = canardMakeAcceptanceFilterConfigForSubject(7509);
+// And to receive only uavcan.register.Access.1.0 services (fixed port ID 384):
+CanardAcceptanceFilterConfig register_access_config = canardMakeAcceptanceFilterConfigForService(384, ins.node_id);
+
+// You can also combine the two filter configurations into one (may also accept in other messages).
+// This allows consolidating a large set of configurations to fit the number of hardware filters.
+// For more information on the optimal subset of configurations to consolidate to minimize wasted CPU,
+// see the UAVCAN specification.
+CanardAcceptanceFilterConfig combined_config = canardConsolidateAcceptanceFilterConfigs(&heartbeat_config, &register_access_config);
+configureHardwareFilters(combined_config.extended_can_id, combined_config.extended_mask);
+```
+
+Full API specification is available in the documentation.
+If you find the examples to be unclear or incorrect, please, open a ticket.
+
 ## Revisions
 
 ### v2.0
-
 - Dedicated transmission queues per redundant CAN interface with depth limits.
   The application is now expected to instantiate `CanardTxQueue` (or several in case of redundant transport) manually.
 
@@ -225,6 +244,8 @@ else
 
 - Support build configuration headers via `CANARD_CONFIG_HEADER`.
 
+- Add API for generating CAN hardware acceptance filter configurations
+
 ### v1.1
 
 - Add new API function `canardRxAccept2()`, deprecate `canardRxAccept()`.