Refactors dbcon into a subsystem

code/__HELPERS/bandetect.dm

@@ -2,7 +2,7 @@
 
 
 /client/proc/join_date_check(y,m,d)
-	var/DBQuery/query_datediff = GLOB.dbcon.NewQuery("SELECT DATEDIFF(Now(),'[y]-[m]-[d]')")
+	var/datum/DBQuery/query_datediff = SSdbcore.NewQuery("SELECT DATEDIFF(Now(),'[y]-[m]-[d]')")
 
 	if(!query_datediff.Execute())
 		return FALSE

code/__HELPERS/text.dm

@@ -15,7 +15,7 @@
 
 // Run all strings to be used in an SQL query through this proc first to properly escape out injection attempts.
 /proc/sanitizeSQL(t)
-	var/sqltext = GLOB.dbcon.Quote("[t]");
+	var/sqltext = SSdbcore.Quote("[t]");
 	return copytext(sqltext, 2, lentext(sqltext));//Quote() adds quotes around input, we already do that
 
 /proc/format_table_name(table as text)