feat: Add wifi network link bitrate value

In order to obtain the RX and TX bitrates from the kernel netlink we need to open a second info socket to get the station data. The values are formatted like "1.9Gb/s" and then exposed as `rx_bitrate` and `tx_bitrate`.
This code is closely following the `iw` implementation.

include/modules/network.hpp

@@ -17,6 +17,8 @@
 #include "util/rfkill.hpp"
 #endif
 
+#define ETH_ALEN 6
+
 enum ip_addr_pref : uint8_t { IPV4, IPV6, IPV4_6 };
 
 namespace waybar::modules {
@@ -34,6 +36,7 @@ class Network : public ALabel {
   static int handleEvents(struct nl_msg*, void*);
   static int handleEventsDone(struct nl_msg*, void*);
   static int handleScan(struct nl_msg*, void*);
+  static int handleStationGet(struct nl_msg *msg, void *data);
 
   void askForStateDump(void);
 
@@ -57,6 +60,7 @@ class Network : public ALabel {
   struct sockaddr_nl nladdr_{0};
   struct nl_sock* sock_{nullptr};
   struct nl_sock* ev_sock_{nullptr};
+  struct nl_sock* station_sock_{nullptr};
   int efd_{-1};
   int ev_fd_{-1};
   int nl80211_id_{-1};
@@ -95,6 +99,8 @@ class Network : public ALabel {
   util::Rfkill rfkill_{RFKILL_TYPE_WLAN};
 #endif
   float frequency_{0};
+  uint32_t tx_bitrate_{0};
+  uint32_t rx_bitrate_{0};
 };
 
 }  // namespace waybar::modules