Add warning when using non-localhost, non-https connection

[ipod86]

I installed luzifer/ots using the provided docker compose under portainer.

When creating a secret nothing happens and the loading circle rotates constantly.

[Luzifer]

You're accessing the site through http. The WebCrypto-API used for the en-/decryption requires access either on http://localhost or using TLS.

Shoud add a warning in the frontend when this is the case…