[low-power] implement enhanced-ack based probing (#5780)

This commit implements Enhanced-ACK Probing (on simulation platform).

- Add a new public API otLinkMetricsConfigEnhAckProbing which sends
  Link Metrics Management Request to configure the probing. This is
  called on Probing Initiator side.

- Add a new radio platform API otPlatRadioConfigureEnhAckProbing. This
  API should be called on Probing Subject side when handling the
  requests from Initiators. This API notifies the radio to start/stop
  aggregating link metrics info and include the data into Vendor IE in
  enhanced-ACK for the specific neighbor. As discussed in #5746, the
  code for doing such thing should be put in radio driver.

- Add a util module util/link_metrics, which provides a group of APIs
  to implement Probing Subject side logic for Enh-ACK Probing. Any
  platform could use this module to implement the feature easily in
  radio driver.

- Add new util APIs in util/mac_frame to generate Enh-ACK Probing IE
  (Vendor IE with Thread OUI and SubType = 0) and set value for this
  IE.

- Update the implementation in simulation/radio.c to support Probing
  Subject side logic for Enh-ACK Probing, using APIs in
  util/link_metrics and util/mac_frame.

- Add a test
  v1_2_LowPower_7_1_01_SingleProbeLinkMetricsWithEnhancedAcks.py for
  testing.

Misc:

  - Add check for all the public Link Metrics APIs (Initiator side) to
    ensure that the Subject is a neighbor of the Initiator. If the
    address is not link-local or the neighbor is not found, an error
    UNKNOWN_NEIGHBOR would be returned.

  - Update PrepareEmptyFrame so that when it's called for reference
    device, its frame version would be set to 2015.

tests/scripts/thread-cert/node.py

@@ -1936,6 +1936,19 @@ class NodeImpl:
         self.send_command(cmd)
         self._expect('Done')
 
+    def link_metrics_mgmt_req_enhanced_ack_based_probing(self,
+                                                         dst_addr: str,
+                                                         enable: bool,
+                                                         metrics_flags: str,
+                                                         ext_flags=''):
+        cmd = "linkmetrics mgmt %s enhanced-ack" % (dst_addr)
+        if enable:
+            cmd = cmd + (" register %s %s" % (metrics_flags, ext_flags))
+        else:
+            cmd = cmd + " clear"
+        self.send_command(cmd)
+        self._expect('Done')
+
     def link_metrics_mgmt_req_forward_tracking_series(self, dst_addr: str, series_id: int, series_flags: str,
                                                       metrics_flags: str):
         cmd = "linkmetrics mgmt %s forward %d %s %s" % (dst_addr, series_id, series_flags, metrics_flags)