I took the configs from this post: https://community.containo.us/t/global-http-to-https-redirect-in-v2/1658/3. This post also mentions the possibility to add a global http redirect with labels to traefik container. But like I said, it didn't work out for me.
[http.routers]
[http.routers.redirecttohttps]
entryPoints = ["web"]
middlewares = ["httpsredirect"]
rule = "HostRegexp(`{host:.+}`)"
service = "noop"
[http.services]
[http.services.noop.loadBalancer]
[[http.services.noop.loadBalancer.servers]]
url = "http://192.168.0.1"
[http.middlewares]
[http.middlewares.httpsredirect.redirectScheme]
scheme = "https"
permanent = true