Add model to represent packages and export information to QML

We'll construct a bunch of these when we receive information from the API.

Contributes to issue CURA-8556.

plugins/Marketplace/PackageModel.py

@@ -0,0 +1,25 @@
+# Copyright (c) 2021 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+
+from PyQt5.QtCore import pyqtProperty, QObject
+
+class PackageModel(QObject):
+    """
+    Represents a package, containing all the relevant information to be displayed about a package.
+
+    Effectively this behaves like a glorified named tuple, but as a QObject so that its properties can be obtained from
+    QML.
+    """
+
+    def __init__(self, package_id: str, display_name: str, parent: QObject = None):
+        super().__init__(parent)
+        self._package_id = package_id
+        self._display_name = display_name
+
+    @pyqtProperty(str, constant = True)
+    def packageId(self) -> str:
+        return self._package_id
+
+    @pyqtProperty(str, constant = True)
+    def displayName(self) -> str:
+        return self._display_name