feat: add security module (#111)

* feat: add security module

* feat(security): add oauth helpers

* docs: add authentication example

* fix: cleanup + simplify

* docs: update module and reference

* fix: multiple security bugs + remove example for now

* feat: use async_lru for caching

* fix: rename nonce by state_token

docs/reference/security.md

@@ -0,0 +1,43 @@
+# `security`
+
+Here's the reference for the authentication helpers provided by the `security` module.
+
+You can import them directly from `fastapi_toolsets.security`:
+
+```python
+from fastapi_toolsets.security import (
+    AuthSource,
+    BearerTokenAuth,
+    CookieAuth,
+    APIKeyHeaderAuth,
+    MultiAuth,
+    oauth_build_authorization_redirect,
+    oauth_decode_state,
+    oauth_encode_state,
+    oauth_fetch_userinfo,
+    oauth_generate_state_token,
+    oauth_resolve_provider_urls,
+)
+```
+
+## ::: fastapi_toolsets.security.AuthSource
+
+## ::: fastapi_toolsets.security.BearerTokenAuth
+
+## ::: fastapi_toolsets.security.CookieAuth
+
+## ::: fastapi_toolsets.security.APIKeyHeaderAuth
+
+## ::: fastapi_toolsets.security.MultiAuth
+
+## ::: fastapi_toolsets.security.oauth_resolve_provider_urls
+
+## ::: fastapi_toolsets.security.oauth_fetch_userinfo
+
+## ::: fastapi_toolsets.security.oauth_generate_state_token
+
+## ::: fastapi_toolsets.security.oauth_build_authorization_redirect
+
+## ::: fastapi_toolsets.security.oauth_encode_state
+
+## ::: fastapi_toolsets.security.oauth_decode_state