Add embeded libregrah/idm server

This add a new service "idm" providing and LDAP service (via ldaps) on
port 9235.  If not existing it will bootstrap an initial LDAP tree and
administrative user as well as a self-signed Certificate and Key
(similar to what is done for glauth).

ocis/pkg/command/idm.go

@@ -0,0 +1,26 @@
+package command
+
+import (
+	"github.com/owncloud/ocis/idm/pkg/command"
+	"github.com/owncloud/ocis/ocis-pkg/config"
+	"github.com/owncloud/ocis/ocis-pkg/config/parser"
+	"github.com/owncloud/ocis/ocis/pkg/register"
+	"github.com/urfave/cli/v2"
+)
+
+// IDMCommand is the entrypoint for the idm server command.
+func IDMCommand(cfg *config.Config) *cli.Command {
+	return &cli.Command{
+		Name:     "idm",
+		Usage:    "idm extension commands",
+		Category: "extensions",
+		Before: func(ctx *cli.Context) error {
+			return parser.ParseConfig(cfg)
+		},
+		Subcommands: command.GetCommands(cfg.IDM),
+	}
+}
+
+func init() {
+	register.AddCommand(IDMCommand)
+}