Import pwic as source, add overrides

This commit imports the latest source of the pwic module directly
and modifies it just enough for it to be an importable module.

Source: https://github.com/gitbra/pwic

test/test_db.py

@@ -0,0 +1,9 @@
+from ttfrog import db
+from ttfrog.pwic.pwic_admin import PwicConst
+
+
+def test_db_init():
+    config = db.init({"SALT": "salt", "DB_DEFAULT_PORT": "012345"})
+    assert config.SALT == "salt"
+    assert config.DEFAULTS["port"] == "012345"
+    assert config.DEFAULTS["page"] == PwicConst.DEFAULTS["page"]