PUI Plugin Panels (#7470)

* Adds basic API endpoint for requesting plugin panels

* Split PanelType out into own file

* Placeholder for a plugin panel loaded dynamically

* Add some dummy data for the plugin panels

* Example of plugin panel selection based on page

* Expose some global window attributes

* Add new setting

* Disable panel return if plugin integration is not enabled

* Update hook to auto-magically load plugin panels

* Allow custom panel integration for more panel  groups

* Remove debug call

* Tweak query return data

* async fn

* Adds <PluginPanel> component for handling panel render

* Cleanup

* Prevent API requests before instance ID is known

* Pass instance data through

* Framework for a sample plugin which implements custom panels

* offload custom panels to sample plugin

* Load raw HTML content

* Expand custom panel rendering demo

* Adjust API endpoints

* Add function to clear out static files which do not match installed plugin(s)

* Update static files when installing plugins from file

* Update static files when installing or uninstalling a plugin

* Update static files on config change

* Pass more information through to plugin panels

* Prepend hostname to plugin source

* Pass instance detail through

* Cleanup code for passing data through to plugin panels

- Define interface type
- Shorten variable names

* Update docs requirements

* Revert "Update docs requirements"

This reverts commit 63a06d97f5.

* Add placeholder for documentation

* Fix imports

* Add a broken panel which tries to load a non-existent javascript file

* Render error message if plugin does not load correctly

* Only allow superuser to perform plugin actions

* Code cleanup

* Add "dynamic" contnt - javascript file - to example plugin

* Remove default values

* Cleanup unused code

* PanelGroup updates

* Cleanup hooks for changing panel state

* More work needed...

* Code cleanup

* More updates / refactoring

- Allow dynamic hiding of a particular panel
- Pass target ref as positional argument
- Better handling of async calls

* Documentation

* Bump API version

* Provide theme object to plugin context

* Adjust sample plugin

* Docs updates

* Fix includefile call in docs

* Improve type annotation

* Cleanup

* Enable plugin panels for "purchasing index" and "sales index" pages

* Fix for plugin query check

* Improvements to panel selection

- Code refactor / cleanup
- Ensure that a valid panel is always displayed
- Allow plugin panels to persist, even after reload

* Playwright test fixes

* Update src/frontend/src/hooks/UsePluginPanels.tsx

Co-authored-by: Lukas <76838159+wolflu05@users.noreply.github.com>

* Update src/frontend/src/components/plugins/PluginPanel.tsx

Co-authored-by: Lukas <76838159+wolflu05@users.noreply.github.com>

* Update src/frontend/src/components/plugins/PluginContext.tsx

Co-authored-by: Lukas <76838159+wolflu05@users.noreply.github.com>

* Fix context

* Add more context data

* Docs updates

* Reimplement local state

* Fix mkdocs.yml

* Expose 'colorScheme' to plugin context

* Define CustomPanel type definition

* Add unit testing for user interface plugins

* Add front-end tests for plugin panels

* Add new setting to plugin_settings_keys

* Adds helper function for annotating build line allocations

* Improve query efficiency

- Especially around unit testing
- Ensure all settings are generated
- Do not auto-create settings during registry load

* Improve query efficiency for build order operations

* Reduce max query count for specific test

* Revert query count limit

* playwright test updates

---------

Co-authored-by: Lukas <76838159+wolflu05@users.noreply.github.com>

docs/docs/extend/plugins/panel.md

@@ -4,6 +4,12 @@ title: Panel Mixin
 
 ## PanelMixin
 
+!!! warning "Legacy User Interface"
+    This plugin mixin class is designed specifically for the the *legacy* user interface (which is rendered on the server using django templates). The new user interface (which is rendered on the client using React) does not support this mixin class. Instead, refer to the new [User Interface Mixin](./ui.md) class.
+
+!!! warning "Deprecated Class"
+    This mixin class is considered deprecated, and will be removed in the 1.0.0 release.
+
 The `PanelMixin` enables plugins to render custom content to "panels" on individual pages in the web interface.
 
 Most pages in the web interface support multiple panels, which are selected via the sidebar menu on the left side of the screen: