allow login using hashed passwords (#4464)

* Support getting a user's password salt via initial websocket connection (added to Event_ServerIdentification)

* Nonsense stuff to figure out later

* move passwordhasher to correct location

* protobuf changes

* add ext to protobuf

* implement request password salt server side

* add supportspasswordhash to server identification

* check backwards compatibility

* reset some changes to master

* implement get password salt client side

* implement checking hashed passwords on server login

* check for registration requirement on getting password salt

* properly check password salt response and show errors

* remove unused property

* add password salt to list of response types

Co-authored-by: ZeldaZach <zahalpern+github@gmail.com>

common/server_database_interface.h

@@ -18,7 +18,8 @@ public:
                                                    const QString &password,
                                                    const QString &clientId,
                                                    QString &reasonStr,
-                                                   int &secondsLeft) = 0;
+                                                   int &secondsLeft,
+                                                   bool passwordNeedsHash) = 0;
     virtual bool checkUserIsBanned(const QString & /* ipAddress */,
                                    const QString & /* userName */,
                                    const QString & /* clientId */,
@@ -35,6 +36,10 @@ public:
     {
         return false;
     }
+    virtual QString getUserSalt(const QString & /* user */)
+    {
+        return {};
+    }
     virtual QMap<QString, ServerInfo_User> getBuddyList(const QString & /* name */)
     {
         return QMap<QString, ServerInfo_User>();