Plugins: Make it possible to support multiple plugin versions (#82116)

* first pass

* use version in more places

* add comment

* update installer

* fix wire

* fix tests

* tidy

* simplify changes

* fix in mem

* remove unused step

* fix step dupe logic for child plugins + add tests

pkg/plugins/manager/registry/ifaces.go

@@ -8,12 +8,12 @@ import (
 
 // Service is responsible for the internal storing and retrieval of plugins.
 type Service interface {
-	// Plugin finds a plugin by its ID.
-	Plugin(ctx context.Context, id string) (*plugins.Plugin, bool)
+	// Plugin finds a plugin by its ID and version.
+	Plugin(ctx context.Context, id, version string) (*plugins.Plugin, bool)
 	// Plugins returns all plugins.
 	Plugins(ctx context.Context) []*plugins.Plugin
 	// Add adds the provided plugin to the registry.
 	Add(ctx context.Context, plugin *plugins.Plugin) error
 	// Remove deletes the requested plugin from the registry.
-	Remove(ctx context.Context, id string) error
+	Remove(ctx context.Context, id, version string) error
 }