api: generate random jwt secret if not present, remove unused imports

internal/common/crypto.go

@@ -1,6 +1,7 @@
 package common
 
 import (
+	"crypto/rand"
 	"encoding/base64"
 
 	"github.com/rs/zerolog/log"
@@ -16,3 +17,12 @@ func decodeJWTKey(key string) []byte {
 	}
 	return bytes
 }
+
+func RandomJWTKey() []byte {
+	key := make([]byte, 32)
+	_, err := rand.Read(key)
+	if err != nil {
+		log.Panic().Err(err).Msg("failed to generate random jwt key")
+	}
+	return key
+}