Lots of tidying

- Removed generic `avr8` target
- Simplified AVR8 target construction
- Introduced register descriptor IDs
- Simplified GDB register mappings
- Simplified target interface contract
- Other bits of tidying

src/DebugToolDrivers/Microchip/EdbgDevice.cpp

@@ -66,7 +66,6 @@ namespace Bloom::DebugToolDrivers
             );
         }
 
-        this->edbgAvr8Interface = std::make_unique<EdbgAvr8Interface>(this->edbgInterface.get());
         this->edbgAvrIspInterface = std::make_unique<EdbgAvrIspInterface>(this->edbgInterface.get());
 
         this->setInitialised(true);
@@ -81,6 +80,27 @@ namespace Bloom::DebugToolDrivers
         UsbDevice::close();
     }
 
+    TargetInterfaces::Microchip::Avr::Avr8::Avr8DebugInterface* EdbgDevice::getAvr8DebugInterface(
+        const Targets::Microchip::Avr::Avr8Bit::Avr8TargetConfig& targetConfig,
+        Targets::Microchip::Avr::Avr8Bit::Family targetFamily,
+        const Targets::Microchip::Avr::Avr8Bit::TargetParameters& targetParameters,
+        const Targets::TargetRegisterDescriptorMapping& targetRegisterDescriptorsById
+    ) {
+        if (this->edbgAvr8Interface == nullptr) {
+            this->edbgAvr8Interface = std::make_unique<EdbgAvr8Interface>(
+                this->edbgInterface.get(),
+                targetConfig,
+                targetFamily,
+                targetParameters,
+                targetRegisterDescriptorsById
+            );
+
+            this->configureAvr8Interface();
+        }
+
+        return this->edbgAvr8Interface.get();
+    }
+
     std::string EdbgDevice::getSerialNumber() {
         using namespace CommandFrames::Discovery;
         using ResponseFrames::Discovery::ResponseId;