Add ai speech

[jlowin]

from marvin.components.ai_speech import ai_speech

@ai_speech
def say_hello(name:str):
    return f'hello there, {name}!'

r = say_hello("Marvin")
r.stream_to_file('./speech.mp3')

[jlowin]

Sitrep: just had a minor panic that "speech" was spelled incorrectly. Need coffee.