Add testing script that generates deck DB with 10**8 cards

Starting SDC with this DB takes 5 seconds to load all the weights from disk (it's 1.9GB), but after that it's incredibly fast and responsive. Yay segment trees and overengineering!

test.py

@@ -0,0 +1,8 @@
+import sqlite3
+
+con = sqlite3.connect("test.db")
+cur = con.cursor()
+cur.execute("CREATE TABLE IF NOT EXISTS cards (idx INTEGER PRIMARY KEY, weight INTEGER, key STRING, val STRING)")
+for i in range(10**8):
+    cur.execute("INSERT INTO cards VALUES(?, ?, ?, ?)", (i, 1, i, i))
+con.commit()