Add new Holidays: The Great War, D&D, and Species Celebrations (#59370)

Adds some new holidays.

    Remembrance Day is self explanatory, and falls on November 11th.
    UN Day is on the anniversary of the foundation of the UN, October 24th.
    Wizards Day is on Gary Gygax's birthday, July 27th.
    Tiziran Unification Day falls on September 1st, and is the date on which Lizards were made a roundstart race.
    The Festival of Atrakor's Might falls on June 15th, and is the date on which the Lizard visual overhaul was merged, bringing horns, frills, and spines to make lizards less bland.
    Draconic Day falls on May 3rd, and is the date on which the Draconic language was merged, heralding the rise of the Lizard metagangs (or not).
    Fleet Day is the Moths' special day, falling on Jan 19th which is the date on which Moths were merged.
    Finally, the Festival of Holy Lights is the Ethereal holiday, falling on Nov 28th, the date on which Ethereals were merged.

code/modules/holiday/holidays.dm

@@ -661,3 +661,94 @@
 /datum/holiday/pride_week/proc/get_floor_tile_color(atom/atom)
 	var/turf/turf = get_turf(atom)
 	return rainbow_colors[(turf.y % rainbow_colors.len) + 1]
+
+/datum/holiday/remembrance_day
+	name = "Remembrance Day"
+	begin_month = NOVEMBER
+	begin_day = 11
+	drone_hat = /obj/item/food/grown/poppy
+
+/datum/holiday/remembrance_day/getStationPrefix()
+	return pick("Peace", "Armistice", "Poppy")
+
+/datum/holiday/un_day
+	name = "Anniversary of the Foundation of the United Nations"
+	begin_month = OCTOBER
+	begin_day = 24
+
+/datum/holiday/un_day/greet()
+	return "On this day in 1945, the United Nations was founded, laying the foundation for humanity's united government!"
+
+/datum/holiday/un_day/getStationPrefix()
+	return pick("United", "Cooperation", "Humanitarian")
+
+//Gary Gygax's birthday, a fitting day for Wizard's Day
+/datum/holiday/wizards_day
+	name = "Wizard's Day"
+	begin_month = JULY
+	begin_day = 27
+	drone_hat = /obj/item/clothing/head/wizard
+
+/datum/holiday/wizards_day/getStationPrefix()
+	return pick("Dungeon", "Elf", "Magic", "D20", "Edition")
+
+//Species cultural holidays, based on days of significant PRs relating to their species
+//Tiziran Unification Day is celebrated on Sept 1st, the day on which lizards were made a roundstart race
+/datum/holiday/tiziran_unification
+	name = "Tiziran Unification Day"
+	begin_month = SEPTEMBER
+	begin_day = 1
+
+/datum/holiday/tiziran_unification/greet()
+	return "On this day over 400 years ago, Lizardkind first united under a single banner, ready to face the stars as one unified people."
+
+/datum/holiday/tiziran_unification/getStationPrefix()
+	return pick("Tizira", "Lizard", "Imperial")
+
+//The Festival of Atrakor's Might (Tizira's Moon) is celebrated on June 15th, the date on which the lizard visual revamp was merged (#9808)
+/datum/holiday/atrakor_festival
+	name = "Festival of Atrakor's Might"
+	begin_month = JUNE
+	begin_day = 15
+
+/datum/holiday/atrakor_festival/greet()
+	return "On this day, the Lizards traditionally celebrate the Festival of Atrakor's Might, where they honour the moon god with lavishly adorned clothing, large portions of food, and a massive celebration into the night."
+
+/datum/holiday/atrakor_festival/getStationPrefix()
+	return pick("Moon", "Night Sky", "Celebration")
+
+//Draconic Day is celebrated on May 3rd, the date on which the Draconic language was merged (#26780)
+/datum/holiday/draconic_day
+	name = "Draconic Language Day"
+	begin_month = MAY
+	begin_day = 3
+
+/datum/holiday/draconic_day/greet()
+	return "On this day, Lizardkind celebrates their language with literature and other cultural works."
+
+/datum/holiday/draconic_day/getStationPrefix()
+	return pick("Draconic", "Literature", "Reading")
+
+//Fleet Day is celebrated on Jan 19th, the date on which moths were merged (#34498)
+/datum/holiday/fleet_day
+	name = "Fleet Day"
+	begin_month = JANUARY
+	begin_day = 19
+
+/datum/holiday/fleet_day/greet()
+	return "This day commemorates another year of successful survival aboard the Mothic Grand Nomad Fleet. Moths galaxywide are encouraged to eat, drink, and be merry."
+
+/datum/holiday/fleet_day/getStationPrefix()
+	return pick("Moth", "Fleet", "Nomadic")
+
+//The Festival of Holy Lights is celebrated on Nov 28th, the date on which ethereals were merged (#40995)
+/datum/holiday/holy_lights
+	name = "Festival of Holy Lights"
+	begin_month = NOVEMBER
+	begin_day = 28
+
+/datum/holiday/holy_lights/greet()
+	return "The Festival of Holy Lights is the final day of the Ethereal calendar. It is typically a day of prayer followed by celebration to close out the year in style."
+
+/datum/holiday/holy_lights/getStationPrefix()
+	return pick("Ethereal", "Lantern", "Holy")