Migrate to python (#265)

* Add initial python migration

* Add pylint

* Add pre-commit

* Add Dockerfile

* Add expression matching

* Use shelve to store previous matches

* Add notifications

* Calculate post age

* Update README.md

rfd_notify/models/post.py

@@ -0,0 +1,8 @@
+class Post:
+    # pylint: disable=unused-argument
+    def __init__(
+        self,
+        body: str,
+        **kwargs,
+    ):
+        self.body = body