Add second `cloud` chain type for Outlook calendar integration

[DiTsi]

Do it in the same way as the Google Calendar integration. Refer to the documentation:

• https://docs.impulse.bot/stable/config_file/#cloud-chain
• https://docs.impulse.bot/stable/google/

Configuration

Introduce a new provider named outlook.
May be we should rename calendar_id option for this integration.

Environment Variables

We should discuss new environment variable names once we fully understand which ones will be required.