refactor: move converter from hrp internal to pkg

hrp/pkg/convert/from_swagger.go

@@ -0,0 +1,24 @@
+package convert
+
+import (
+	"github.com/go-openapi/spec"
+	"github.com/pkg/errors"
+
+	"github.com/httprunner/httprunner/v4/hrp"
+	"github.com/httprunner/httprunner/v4/hrp/internal/builtin"
+)
+
+func LoadSwaggerCase(path string) (*hrp.TCase, error) {
+	// load swagger file
+	caseSwagger := new(spec.Swagger)
+	err := builtin.LoadFile(path, caseSwagger)
+	if err != nil {
+		return nil, errors.Wrap(err, "load swagger file failed")
+	}
+	if caseSwagger.Definitions == nil {
+		return nil, errors.New("invalid swagger case file, missing definitions")
+	}
+
+	// TODO: convert swagger to TCase
+	return nil, nil
+}