refactor: improve error handling in DID module

x/service/types/errors.go

@@ -0,0 +1,9 @@
+package types
+
+import sdkerrors "cosmossdk.io/errors"
+
+var (
+	ErrInvalidGenesisState  = sdkerrors.Register(ModuleName, 100, "invalid genesis state")
+	ErrInvalidServiceOrigin = sdkerrors.Register(ModuleName, 200, "invalid service origin")
+	ErrUnrecognizedService  = sdkerrors.Register(ModuleName, 201, "unrecognized service")
+)