Plugins: Split plugin manager into smaller components (#54384)

* split out plugin manager

* remove whitespace

* fix tests

* split up tests

* updating naming conventions

* simplify manager

* tidy

* add more fakes

* testing time

* add query verif to int test

* renaming

* add process tests

* tidy up manager tests

* add extra case to int test

* add more coverage to store and process tests

* remove comment

* fix capatilization

* init on provide

* remove addfromsource from API

pkg/plugins/plugins.go

@@ -206,7 +206,6 @@ func (p *Plugin) Start(ctx context.Context) error {
 	if p.client == nil {
 		return fmt.Errorf("could not start plugin %s as no plugin client exists", p.ID)
 	}
-
 	return p.client.Start(ctx)
 }