FLEX pager app (#2883)

* Add FLEX pager support

- Introduced a new FLEX configuration function in baseband_api.
- Added FLEX application view and associated UI elements.
- Implemented FLEX processing logic in proc_flex, including demodulation and message handling.
- Updated CMakeLists to include new FLEX source files and headers.
- Enhanced message system to support FLEX-specific messages and statistics.

This commit lays the groundwork for FLEX pager functionality, allowing for the reception and processing of FLEX messages.

* Fixed baseband and moved app to external with some other fixes.

* Format code

---------

Co-authored-by: RocketGod <57732082+RocketGod-git@users.noreply.github.com>

firmware/common/message.hpp

@@ -35,6 +35,7 @@
 #include "adsb_frame.hpp"
 #include "ert_packet.hpp"
 #include "pocsag_packet.hpp"
+#include "flex_defs.hpp"
 #include "aprs_packet.hpp"
 #include "sonde_packet.hpp"
 #include "tpms_packet.hpp"
@@ -136,6 +137,10 @@ class Message {
         NoaaAptRxImageData = 79,
         FSKPacket = 80,
         EPIRBPacket = 81,
+        FlexPacket = 82,
+        FlexStats = 83,
+        FlexConfigure = 84,
+        FlexDebug = 85,
         MAX
     };
 
@@ -1569,4 +1574,49 @@ class NoaaAptRxImageDataMessage : public Message {
     uint32_t cnt = 0;
 };
 
+class FlexPacketMessage : public Message {
+   public:
+    constexpr FlexPacketMessage(const flex::FlexPacket& packet)
+        : Message{ID::FlexPacket},
+          packet{packet} {
+    }
+    flex::FlexPacket packet;
+};
+
+class FlexStatsMessage : public Message {
+   public:
+    constexpr FlexStatsMessage(const flex::FlexStats& stats)
+        : Message{ID::FlexStats},
+          stats{stats} {
+    }
+    flex::FlexStats stats;
+};
+
+class FlexConfigureMessage : public Message {
+   public:
+    constexpr FlexConfigureMessage()
+        : Message{ID::FlexConfigure} {
+    }
+};
+
+class FlexDebugMessage : public Message {
+   public:
+    constexpr FlexDebugMessage(const uint32_t val1, const uint32_t val2, const char* msg)
+        : Message{ID::FlexDebug},
+          val1{val1},
+          val2{val2},
+          text{} {
+        size_t i = 0;
+        while (i < sizeof(text) - 1 && msg[i] != '\0') {
+            text[i] = msg[i];
+            i++;
+        }
+        text[i] = '\0';
+    }
+
+    uint32_t val1;
+    uint32_t val2;
+    char text[64];
+};
+
 #endif /*__MESSAGE_H__*/