Blacken and isort code, add pre-commit and CI linting

.pre-commit-config.yaml

@@ -0,0 +1,19 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.4.0
+    hooks:
+      - id: trailing-whitespace
+        exclude_types: [markdown]
+      - id: end-of-file-fixer
+      - id: check-added-large-files
+  - repo: https://github.com/psf/black
+    rev: 23.9.1
+    hooks:
+      - id: black
+        language_version: python3
+        files: ^rss/.*\.pyi?$
+  - repo: https://github.com/PyCQA/isort
+    rev: 5.12.0
+    hooks:
+      - id: isort
+        files: ^rss/.*\.pyi?$