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>
Co-authored-by: tobozo <tobozo@users.noreply.github.com>
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>
Co-authored-by: Loick MAHIEUX <loick111@gmail.com>
Co-authored-by: Larry Bernstone <lbernstone@gmail.com>
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Co-authored-by: Clemens Kirchgatterer <clemens@1541.org>
Co-authored-by: Aron Rubin <aronrubin@gmail.com>
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libraries/README.md

@@ -61,6 +61,9 @@ arduino-esp32 includes libraries for Arduino compatibility along with some objec
 ### Preferences
   Flash keystore using ESP32 NVS
 
+### ESP RainMaker
+  End-to-end platform by Espressif that enables Makers to realize their IoT ideas faster
+
 ### SD
   Secure Digital card filesystem using SPI access