tips: add tips that villages can be lures, and losses are necessary

From oaq's post https://forums.wesnoth.org/viewtopic.php?f=3&t=47702

Kai Laudiss is Kai Krellis' dad, and the quote would be 3 years
before Dead Water.

data/tips.cfg

@@ -148,6 +148,10 @@
     text= _ "Try to avoid moving next to unoccupied villages. An enemy unit may move into the village and attack you, while enjoying the defense and healing of the village."
     source= _ "<i>― Great Mage Delfador, 516YW</i>"
 [/tip]
+[tip]
+    text= _ "For any player, controlling villages is often key to winning a scenario. You may use this knowledge to lure your opponents into a trap by leaving some villages unoccupied, but keep in mind that an enemy unit becomes much harder to dislodge from a village! Plan your movements accordingly."
+    source= _ "<i>― Kai Laudiss, 623YW</i>"
+[/tip]
 [tip]
     text= _ "Use lines of troops to screen your injured units while they recover."
     source= _ "<i>― Princess Li’sar, 515YW</i>"
@@ -248,6 +252,10 @@
     text= _  "The recruitment cost of some units may exceed the usual recall expenditure of 20 gold. In a campaign, always check if recalling a unit of the same type may be cheaper."
     source= _ "<i>― The Wesnoth Tactical Guide</i>"
 [/tip]
+[tip]
+    text= _ "You must accept some losses in battle. It is not uncommon for beginners to lose sight of victory as they attempt to keep every unit alive."
+    source= _ "<i>― Queen Asheviere, 503YW</i>"
+[/tip]
 #ifdef __UNUSED__
 [tip]
     text= _ "<i>Feral</i> units, such as Bats and wild animals, will avoid villages. Even if they occupy a village hex, they do not gain any defensive benefits from the village, although they will still be healed."