allow to encrypt keys in db, add browser-only key generator, add hints that private keys are stored on the server (#420)

internal/domain/crypto.go

@@ -7,7 +7,7 @@ import (
 )
 
 type KeyPair struct {
-	PrivateKey string
+	PrivateKey string `gorm:"serializer:encstr"`
 	PublicKey  string
 }