added support to login user oauth user by email only (#6330)

* added support to login user oauth user by email only

* added sql handler

* fixed model method name from GetUserByEmail to GetUserByEmailQuery

* fixed variable declaration typo

pkg/api/login_oauth.go

@@ -130,7 +130,7 @@ func OAuthLogin(ctx *middleware.Context) {
 		return
 	}
 
-	userQuery := m.GetUserByLoginQuery{LoginOrEmail: userInfo.Email}
+	userQuery := m.GetUserByEmailQuery{Email: userInfo.Email}
 	err = bus.Dispatch(&userQuery)
 
 	// create account if missing