feat: emoji reactions for tasks and comments (#2196)

This PR adds reactions for tasks and comments, similar to what you can do on Gitea, GitHub, Slack and plenty of other tools.

Reviewed-on: https://kolaente.dev/vikunja/vikunja/pulls/2196
Co-authored-by: kolaente <k@knt.li>
Co-committed-by: kolaente <k@knt.li>

pkg/modules/migration/trello/trello.go

@@ -25,6 +25,7 @@ import (
 	"code.vikunja.io/api/pkg/models"
 	"code.vikunja.io/api/pkg/modules/migration"
 	"code.vikunja.io/api/pkg/user"
+
 	"github.com/adlio/trello"
 	"github.com/yuin/goldmark"
 )