[PC-1186] Nicla Voice Alexa Demo Fix (#972)

* Initial commit

* Alexa demo section content update

* Overview section content update

* Content update

* Content update

* Numbered list fix

* Content update

* Update content/hardware/06.nicla/boards/nicla-voice/tutorials/getting-started-ml/content.md

Co-authored-by: Julián Caro Linares <j.carolinares@arduino.cc>

* Content update, links fix

* Tutorial title updated

* Content update, tutorial title

* Linter fix

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Co-authored-by: Julián Caro Linares <j.carolinares@arduino.cc>

Author: canchebagur