Placeholder Plugin Providers for Repos and added testPlugin struct (#1532)

* Create minimalistic plugin map and test plugin.

* Pass secrets and attributes to the plugin when creating catalogs or sets.  Add tests for CreateSet and CreateCatalog repo methods.

* make fmt and extract out getPrivateCatalog and getCatalog helper methods.

* Exporting TestPluginServer so it can be used in the handlers.

* Keep separate persisted data from host catalogs lookups which facilitate passing it onto the plugins.

* Add TODO to merge get Catalog and get Persisted data.

* Adding tests for unimplemented being returned by the plugin.

* Use GetFields() instead of AsMap() to confirm attributes should be populated. Make clone consistent between catalog and sets.

Co-authored-by: Jeff Mitchell <jeffrey.mitchell@gmail.com>

internal/servers/controller/controller.go

@@ -24,6 +24,7 @@ import (
 	"github.com/hashicorp/boundary/internal/servers/controller/common"
 	"github.com/hashicorp/boundary/internal/session"
 	"github.com/hashicorp/boundary/internal/target"
+	plgpb "github.com/hashicorp/boundary/sdk/pbs/plugin"
 	"github.com/hashicorp/go-hclog"
 	"github.com/hashicorp/go-secure-stdlib/mlock"
 	"github.com/patrickmn/go-cache"
@@ -136,7 +137,7 @@ func New(ctx context.Context, conf *Config) (*Controller, error) {
 		return static.NewRepository(dbase, dbase, c.kms)
 	}
 	c.PluginHostRepoFn = func() (*hostplugin.Repository, error) {
-		return hostplugin.NewRepository(dbase, dbase, c.kms)
+		return hostplugin.NewRepository(dbase, dbase, c.kms, map[string]plgpb.HostPluginServiceServer{})
 	}
 	c.HostPluginRepoFn = func() (*host.Repository, error) {
 		return host.NewRepository(dbase, dbase, c.kms)