Add support for Shelly Dimmer 2 (#2954)

Co-authored-by: Niclas Larsson <niclas@edgesystems.se>
Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>
Co-authored-by: Jernej Kos <jernej@kos.mx>
Co-authored-by: Richard Nauber <richard@nauber.dev>

CODEOWNERS

@@ -173,6 +173,7 @@ esphome/components/select/* @esphome/core
 esphome/components/sensirion_common/* @martgras
 esphome/components/sensor/* @esphome/core
 esphome/components/sgp40/* @SenexCrenshaw
+esphome/components/shelly_dimmer/* @edge90 @rnauber
 esphome/components/sht4x/* @sjtrny
 esphome/components/shutdown/* @esphome/core @jsuanet
 esphome/components/sim800l/* @glmnet