Adds Random Notes (#5644)

Adds SSDocs, which manages randomly spawned documents.
    These documents can be specified in a json file or in a database.
    Adds /obj/random/document and adds /obj/random/document to the loot pool of /obj/random/loot.

Actually adding the notes to spawn is up to loredevs. If there are no notes to choose from, /obj/random/document will leave a blank sheet.

The notes can have HTML in them, meaning custom CSS and images. We're giving the loredevs a good bit of responsibility here.

code/controllers/configuration.dm

@@ -283,6 +283,9 @@ var/list/gamemode_cache = list()
 
 	var/rounds_until_hard_restart = -1 // Changes how often a hard restart will be executed.
 
+	var/docs_load_docs_from
+	var/docs_image_host
+ 
 	var/ert_base_chance = 10
 	var/ert_green_inc = 1
 	var/ert_yellow_inc = 1
@@ -886,6 +889,11 @@ var/list/gamemode_cache = list()
 				if ("rounds_until_hard_restart")
 					rounds_until_hard_restart = text2num(value)
 
+				if ("docs_load_docs_from")
+					docs_load_docs_from = value
+				if ("docs_image_host")
+					docs_image_host = value
+
 				if ("ert_base_chance")
 					ert_base_chance = text2num(value)
 				if ("ert_green_inc")