Builtin plugins (#3889)

* Allow loading of "builtin" plugins, even if "plugins" are not explicitly loaded

* Updates for 'admin' buttons:

- Make them work like proper links
- Hidden if 'hide_admin_link' customization option is set
- Check for user staff status

* Cleanup rendering of "plugins" display

* Consolidate InvenTree barcode plugins into single plugin class

* Hide "install plugin" button if plugins are not enabled

* Add info message is external plugins are not enabled

* Fixes for loading plugins

- Always load 'builtin' plugins
- Refactor calls to "is_active" at various points in codebase

* Various tweaks

- Improve builtin plugin descriptions
- Spelling fixes

* Adjust plugin detail for builtin plugins

* Simplify barcode plugin class

* Simplify template rendering

* Bug fix for inventree barcode plugin

* Revert "Simplify template rendering"

This reverts commit 3a6755a659.

* Re-re-improve template rendering

- Required as the template has been refactored for both "active" and "inactive" plugins

* Fixing unit tests for barcode plugin

* Ensure that barcode scan actions do not take a "long time":

- Add a default timeout of 0.1s to any POST or GET request in the testing framework
- Can be overridden by calling method if desired

* Display plugin "builtin" status in admin panel

* Fix unit tests for plugin API

* Further unit testing fixes

* Version number tweaks

* Further tweaks for unit testing

* Allow longer timeout for report printing via API

* Increase default timeout for API tests

- Sometimes CPU spike can cause the test to fail :|

* label printing can take a bit longer

* Remove timeout requirement from API tester

- Too variable to be reliable for CI

InvenTree/plugin/test_api.py

@@ -28,25 +28,38 @@ class PluginDetailAPITest(PluginMixin, InvenTreeAPITestCase):
         url = reverse('api-plugin-install')
 
         # valid - Pypi
-        data = self.post(url, {
-            'confirm': True,
-            'packagename': self.PKG_NAME
-        }, expected_code=201).data
+        data = self.post(
+            url,
+            {
+                'confirm': True,
+                'packagename': self.PKG_NAME
+            },
+            expected_code=201,
+        ).data
+
         self.assertEqual(data['success'], True)
 
         # valid - github url
-        data = self.post(url, {
-            'confirm': True,
-            'url': self.PKG_URL
-        }, expected_code=201).data
+        data = self.post(
+            url,
+            {
+                'confirm': True,
+                'url': self.PKG_URL
+            },
+            expected_code=201,
+        ).data
         self.assertEqual(data['success'], True)
 
         # valid - github url and packagename
-        data = self.post(url, {
-            'confirm': True,
-            'url': self.PKG_URL,
-            'packagename': 'minimal',
-        }, expected_code=201).data
+        data = self.post(
+            url,
+            {
+                'confirm': True,
+                'url': self.PKG_URL,
+                'packagename': 'minimal',
+            },
+            expected_code=201,
+        ).data
         self.assertEqual(data['success'], True)
 
         # invalid tries
@@ -57,17 +70,20 @@ class PluginDetailAPITest(PluginMixin, InvenTreeAPITestCase):
         data = self.post(url, {
             'confirm': True,
         }, expected_code=400).data
+
         self.assertEqual(data['url'][0].title().upper(), self.MSG_NO_PKG.upper())
         self.assertEqual(data['packagename'][0].title().upper(), self.MSG_NO_PKG.upper())
 
         # not confirmed
         self.post(url, {
             'packagename': self.PKG_NAME
-        }, expected_code=400).data
+        }, expected_code=400)
+
         data = self.post(url, {
             'packagename': self.PKG_NAME,
             'confirm': False,
         }, expected_code=400).data
+
         self.assertEqual(data['confirm'][0].title().upper(), 'Installation not confirmed'.upper())
 
     def test_admin_action(self):