feat: add caldav tokens (#1065)

# Description

This PR adds API routes to create and manage caldav tokens. These tokens can be used instead of a user password - required for users who are using external auth providers and don't have a password.

Fixes #842

Frontend: https://kolaente.dev/vikunja/frontend/pulls/1186

Co-authored-by: kolaente <k@knt.li>
Reviewed-on: https://kolaente.dev/vikunja/api/pulls/1065

pkg/user/caldav_token.go

@@ -0,0 +1,40 @@
+// Vikunja is a to-do list application to facilitate your life.
+// Copyright 2018-2021 Vikunja and contributors. All rights reserved.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public Licensee as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program 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 Affero General Public Licensee for more details.
+//
+// You should have received a copy of the GNU Affero General Public Licensee
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package user
+
+import "code.vikunja.io/api/pkg/db"
+
+func GenerateNewCaldavToken(u *User) (token *Token, err error) {
+	s := db.NewSession()
+	defer s.Close()
+
+	return generateHashedToken(s, u, TokenCaldavAuth)
+}
+
+func GetCaldavTokens(u *User) (tokens []*Token, err error) {
+	s := db.NewSession()
+	defer s.Close()
+
+	return getTokensForKind(s, u, TokenCaldavAuth)
+}
+
+func DeleteCaldavTokenByID(u *User, id int64) error {
+	s := db.NewSession()
+	defer s.Close()
+
+	return removeTokenByID(s, u, TokenCaldavAuth, id)
+}