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/Targets/TargetDescriptor.hpp

@@ -4,6 +4,7 @@
 #include <cstdint>
 #include <vector>
 #include <map>
+#include <algorithm>
 #include <QMetaType>
 
 #include "TargetMemory.hpp"
@@ -18,10 +19,40 @@ namespace Bloom::Targets
         std::string id;
         std::string vendorName;
         std::map<TargetMemoryType, TargetMemoryDescriptor> memoryDescriptorsByType;
-        std::map<TargetRegisterType, TargetRegisterDescriptors> registerDescriptorsByType;
+        std::map<TargetRegisterDescriptorId, TargetRegisterDescriptor> registerDescriptorsById;
         std::vector<TargetVariant> variants;
 
         TargetMemoryType programMemoryType;
+
+        TargetDescriptor(
+            std::string id,
+            std::string name,
+            std::string vendorName,
+            std::map<TargetMemoryType, TargetMemoryDescriptor> memoryDescriptorsByType,
+            std::map<TargetRegisterDescriptorId, TargetRegisterDescriptor> registerDescriptorsById,
+            std::vector<TargetVariant> variants,
+            TargetMemoryType programMemoryType
+        )
+            : name(name)
+            , id(id)
+            , vendorName(vendorName)
+            , memoryDescriptorsByType(memoryDescriptorsByType)
+            , registerDescriptorsById(registerDescriptorsById)
+            , variants(variants)
+            , programMemoryType(programMemoryType)
+        {}
+
+        TargetRegisterDescriptorIds registerDescriptorIdsForType(TargetRegisterType type) {
+            auto output = TargetRegisterDescriptorIds();
+
+            for (const auto& [descriptorId, descriptor] : this->registerDescriptorsById) {
+                if (descriptor.type == type) {
+                    output.insert(descriptorId);
+                }
+            }
+
+            return output;
+        }
     };
 }