Add display_messages() function to Logbook and call it on loading the game.

This fixes the problem of messages being displayed only after the logbook.hide() is called.
Translated using Weblate (Korean)

Currently translated at 98.8% (824 of 834 strings)
Add two missing-yet-required unit attributes to swordsman.yaml
Translated using Weblate (Polish)

Currently translated at 7.4% (2 of 27 strings)

our colors -  chyba najlepiej oddaje to 'nasze flagi', 'nasza bandera' choć bandera nie ma raczej konotacji z lądem
Translated using Weblate (Lithuanian)

Currently translated at 38.6% (322 of 834 strings)
Translated using Weblate (Polish)

Currently translated at 47.4% (396 of 834 strings)
Translated using Weblate (Lithuanian)

Currently translated at 6.2% (12 of 191 strings)
Translated using Weblate (Polish)

Currently translated at 100.0% (22 of 22 strings)
Translated using Weblate (Polish)

Currently translated at 47.9% (400 of 834 strings)
Translated using Weblate (Polish)

Currently translated at 90.9% (20 of 22 strings)
Translated using Weblate (Polish)

Currently translated at 62.9% (17 of 27 strings)
Translated using Weblate (Finnish)

Currently translated at 92.4% (771 of 834 strings)
Translated using Weblate (Indonesian)

Currently translated at 100.0% (22 of 22 strings)
Translated using Weblate (Finnish)

Currently translated at 92.9% (775 of 834 strings)

Pyritty saamaan The Sims -tyylisesti samat alkukirjaimet - ei suoria käännöksiä (rivit 350-360)
Translated using Weblate (Indonesian)

Currently translated at 23.1% (193 of 834 strings)
Translated using Weblate (Finnish)

Currently translated at 100.0% (191 of 191 strings)
Translated using Weblate (Polish)

Currently translated at 97.3% (186 of 191 strings)
Translated using Weblate (Finnish)

Currently translated at 37.0% (10 of 27 strings)
Translated using Weblate (Indonesian)

Currently translated at 3.7% (1 of 27 strings)
Merge pull request #2103 from unknown-horizons/scenario_message

Fix scenario messages being displayed only after Logbook is hidden.