[minor] Add Slack notification for ROKS provisioning

[terc1997]

Changes

• Create function notifiyProvisionRoks() that has the same function as notifyProvisionFyre(), however it loads information for ROKS.
• Created an additional parameter --add-details that loads another section to the message block. This was implemented specifically for ROKS, since in our Personal FVT it will require additional messaging with BUSINESS_JUSTIFICATION.
• Add broadcast function, which allows SLACK_CHANNEL to be a string with multiple channels, like SLACK_CHANNEL=channel1,channel2,channel3. All of them will receive the message.
• Fix some small code smells

Tests

The screenshot below shows the test with and without add-details flag.