refactor: tidy up tls cert stuff

internal/config/tls/cert_store_linux.go

@@ -0,0 +1,26 @@
+// Copyright (c) 2021 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package tls
+
+func (t *TLS) InstallCerts() error {
+	return nil // Linux doesn't have a root cert store.
+}
+
+func (t *TLS) UninstallCerts() error {
+	return nil // Linux doesn't have a root cert store.
+}