PluginExtensions: Added support for sharing functions (#98888)

* feat: add generic plugin extension functions

* updated betterer.

* Fixed type issues after sync with main.

* Remved extensions from datasource and panel.

* Added validation for extension function registry.

* Added tests and validation logic for function extensions registry.

* removed prop already existing on base.

* fixed lint error.

---------

Co-authored-by: Marcus Andersson <marcus.andersson@grafana.com>

packages/grafana-runtime/src/services/pluginExtensions/getPluginExtensions.ts

@@ -1,4 +1,9 @@
-import type { PluginExtension, PluginExtensionLink, PluginExtensionComponent } from '@grafana/data';
+import type {
+  PluginExtension,
+  PluginExtensionLink,
+  PluginExtensionComponent,
+  PluginExtensionFunction,
+} from '@grafana/data';
 
 import { isPluginExtensionComponent, isPluginExtensionLink } from './utils';
 
@@ -52,6 +57,16 @@ export type UsePluginLinksResult = {
   links: PluginExtensionLink[];
 };
 
+export type UsePluginFunctionsOptions = {
+  extensionPointId: string;
+  limitPerPlugin?: number;
+};
+
+export type UsePluginFunctionsResult<Signature> = {
+  isLoading: boolean;
+  functions: Array<PluginExtensionFunction<Signature>>;
+};
+
 let singleton: GetPluginExtensions | undefined;
 
 export function setPluginExtensionGetter(instance: GetPluginExtensions): void {