v2.0.0 Add support for ESP32S2 and update ESP-IDF to 4.4 (#4996)

This is very much still work in progress and much more will change before the final 2.0.0

Some APIs have changed. New libraries have been added. LittleFS included.

Co-authored-by: Seon Rozenblum <seonr@3sprockets.com>
Co-authored-by: Me No Dev <me-no-dev@users.noreply.github.com>
Co-authored-by: geeksville <kevinh@geeksville.com>
Co-authored-by: Mike Dunston <m_dunston@comcast.net>
Co-authored-by: Unexpected Maker <seon@unexpectedmaker.com>
Co-authored-by: Seon Rozenblum <seonr@3sprockets.com>
Co-authored-by: microDev <70126934+microDev1@users.noreply.github.com>
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Co-authored-by: bobobo1618 <bobobo1618@users.noreply.github.com>
Co-authored-by: lorol <lorolouis@gmail.com>
Co-authored-by: geeksville <kevinh@geeksville.com>
Co-authored-by: Limor "Ladyada" Fried <limor@ladyada.net>
Co-authored-by: Sweety <switi.mhaiske@espressif.com>
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libraries/RainMaker/README.md

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+# ESP RainMaker library for Arduino
+This library allows to work with ESP RainMaker.
+
+ESP RainMaker is an end-to-end solution offered by Espressif to enable remote control and monitoring for ESP32-S2 and ESP32 based products without any configuration required in the Cloud. The primary components of this solution are:
+
+- Claiming Service (to get the Cloud connectivity credentials)
+- RainMaker library (i.e. this library, to develop the firmware)
+- RainMaker Cloud (backend, offering remote connectivity)
+- RainMaker Phone App/CLI (Client utilities for remote access)
+
+The key features of ESP RainMaker are:
+
+1. Ability to define own devices and parameters, of any type, in the firmware.
+2. Zero configuration required on the Cloud.
+3. Phone apps that dynamically render the UI as per the device information.
+
+This ESP RainMaker library is built using esp-rainmaker component.
+
+#### Repository Source
+
+- [ESP RainMaker](https://github.com/espressif/esp-rainmaker)
+
+## Phone Apps
+
+#### Android
+
+- [Google PlayStore](https://play.google.com/store/apps/details?id=com.espressif.rainmaker)
+- [Direct APK](https://github.com/espressif/esp-rainmaker/wiki)
+- [Source Code](https://github.com/espressif/esp-rainmaker-android)
+
+#### iOS
+- [Apple App Store](https://apps.apple.com/app/esp-rainmaker/id1497491540)
+- [Source Code](https://github.com/espressif/esp-rainmaker-ios)
+
+## Documentation
+
+Additional information about ESP RainMaker can be found [here](https://rainmaker.espressif.com/)
+
+NOTE : ESP RainMaker library is currently supported for ESP32 board only.