Part parameters (#224)

* Adds class representing the PartParameter model

* Adds API method for determining support for PartParmaters

* Display part parameter count in part detail widget

* Adds user setting for controlling if part parameters are displayed

* Fix URL for model

* Widget for displaying part parameters

* linting

lib/widget/part_parameter_widget.dart

@@ -0,0 +1,105 @@
+import "package:flutter/material.dart";
+import "package:inventree/inventree/model.dart";
+
+import "package:inventree/l10.dart";
+import "package:inventree/inventree/part.dart";
+import "package:inventree/widget/paginator.dart";
+import "package:inventree/widget/refreshable_state.dart";
+
+/*
+ * Widget for displaying a list of parameters associated with a given Part instance
+ */
+class PartParameterWidget extends StatefulWidget {
+
+  const PartParameterWidget(this.part);
+
+  final InvenTreePart part;
+
+  @override
+  _ParameterWidgetState createState() => _ParameterWidgetState();
+}
+
+
+class _ParameterWidgetState extends RefreshableState<PartParameterWidget> {
+  _ParameterWidgetState();
+
+  @override
+  String getAppBarTitle(BuildContext context) {
+    return L10().parameters;
+  }
+
+  @override
+  List<Widget> getAppBarActions(BuildContext context) {
+    return [];
+  }
+
+  @override
+  Widget getBody(BuildContext context) {
+
+    Map<String, String> filters = {
+      "part": widget.part.pk.toString()
+    };
+
+    return Column(
+      children: [
+        Expanded(
+          child: PaginatedParameterList(
+            filters,
+            false,
+          )
+        )
+      ],
+    );
+  }
+}
+
+
+/*
+ * Widget for displaying a paginated list of Part parameters
+ */
+class PaginatedParameterList extends PaginatedSearchWidget {
+
+  const PaginatedParameterList(Map<String, String> filters, bool showSearch) : super(filters: filters, showSearch: showSearch);
+
+  @override
+  _PaginatedParameterState createState() => _PaginatedParameterState();
+}
+
+
+class _PaginatedParameterState extends PaginatedSearchState<PaginatedParameterList> {
+
+  _PaginatedParameterState() : super();
+
+  @override
+  String get prefix => "parameters_";
+
+  @override
+  Map<String, String> get orderingOptions => {
+    // TODO
+  };
+
+  @override
+  Map<String, Map<String, dynamic>> get filterOptions => {
+    // TODO
+  };
+
+  @override
+  Future<InvenTreePageResponse?> requestPage(int limit, int offset, Map<String, String> params) async {
+
+    final page = await InvenTreePartParameter().listPaginated(limit, offset, filters: params);
+
+    return page;
+  }
+
+  @override
+  Widget buildItem(BuildContext context, InvenTreeModel model) {
+
+    InvenTreePartParameter parameter = model as InvenTreePartParameter;
+
+    return ListTile(
+      title: Text(parameter.name),
+      subtitle: Text(parameter.description),
+      trailing: Text(parameter.valueString),
+    );
+  }
+}