[sendspin] Add a group media player controller (PR3) (#15948)

Co-authored-by: Copilot <copilot@github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: pre-commit-ci-lite[bot] <117423508+pre-commit-ci-lite[bot]@users.noreply.github.com>
Co-authored-by: J. Nick Koston <nick@koston.org>

CODEOWNERS

@@ -441,6 +441,7 @@ esphome/components/sen21231/* @shreyaskarnik
 esphome/components/sen5x/* @martgras
 esphome/components/sen6x/* @martgras @mebner86 @mikelawrence @tuct
 esphome/components/sendspin/* @kahrendt
+esphome/components/sendspin/media_player/* @kahrendt
 esphome/components/sensirion_common/* @martgras
 esphome/components/sensor/* @esphome/core
 esphome/components/serial_proxy/* @kbx81