Added reauth flow, much better error handling on setup

### Feature
* Now supports reauthentication if credentials have expired/no longer work
* Better error handling when configuring integration, will notify user of incorrect credentials

### Fix
* Removed Owlet specific constants, now using homeassistant generic constants
* On initialisation the integration would crash when trying to update the auth token, the integration would then have to be deleted and setup again

info.md

@@ -0,0 +1,39 @@
+# Owlet Custom Integration
+
+[![GitHub Release][releases-shield]][releases]
+[![GitHub Activity][commits-shield]][commits]
+
+[![License][license-shield]][license]
+
+[![hacs][hacsbadge]][hacs]
+[![Project Maintenance][maintenance-shield]][user_profile]
+
+A custom component for the Owlet smart sock, currently this only supports the owlet smart sock 3.
+
+If you have a smart sock 2 and would like to contribute then please do so.
+
+## Installation
+
+1. Click install.
+2. Reboot Home Assistant.
+3. Hard refresh browser cache.
+4. [![Add Integration][add-integration-badge]][add-integration] or in the HA UI go to "Configuration" -> "Integrations" click "+" and search for "Owlet Smart Sock".
+
+{% endif %}
+
+<!---->
+
+---
+
+[commits-shield]: https://img.shields.io/github/commit-activity/w/RyanClark123/owlet?style=for-the-badge
+[commits]: https://github.com/RyanClark123/owlet/commits/main
+[hacs]: https://github.com/hacs/integration
+[hacsbadge]: https://img.shields.io/badge/HACS-Custom-orange.svg?style=for-the-badge
+[license]: LICENSE
+[license-shield]: https://img.shields.io/github/license/RyanClark123/owlet.svg?style=for-the-badge
+[maintenance-shield]: https://img.shields.io/badge/maintainer-Ryan%20Clark%20%40RyanClark123-blue.svg?style=for-the-badge
+[releases-shield]: https://img.shields.io/github/release/RyanClark123/owlet.svg?style=for-the-badge
+[releases]: https://github.com/RyanClark123/owlet/releases
+[user_profile]: https://github.com/RyanClark123
+[add-integration]: https://my.home-assistant.io/redirect/config_flow_start?domain=owlet
+[add-integration-badge]: https://my.home-assistant.io/badges/config_flow_start.svg