license compliance stuff and other changes

relicense to AGPLv3
comply with the MPL's file copyleft
some other changes in the direction of supporting GPT-2 which were hard to untangle from the rest of the changes (sorry)

utils.py

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: AGPL-3.0-only
+
+import anyio
+import functools
+from bs4 import BeautifulSoup
+
+def shield(f):
+	@functools.wraps(f)
+	async def shielded(*args, **kwargs):
+		with anyio.CancelScope(shield=True) as cs:
+			return await f(*args, **kwargs)
+	return shielded