update the help message (in-app)

[omegabytes]

The help message needs to be updated to reflect the new intents and usages.

This could be as simple as updating the "HELP_MESSAGE" in languageStrings.js.

Ideally, we should look at expanding this into its own intent, so we can achieve more specific and multilevel help messages. Right now, the messages are too long, and we need to be sensitive to how long a user is willing to listen to Alexa drone on. This is a major task.

[Eldres]

HELP_MESSAGE has been updated to include newest additions. Will need to more work/revised if we add more

[omegabytes]

see #101