New: Maintenance Window feature

With the new Maintenance Window feature, you can set a time frame for any monitor, when you know you have maintenance work and it is likely to go down.

The maintenance time frame can be either daily, between certain times, or on a specific date and time.

Other improvements and fixes

• feat: new feature Maintenance Window (#90)
• feat: add ID to sign in form elements
• fix: don’t duplicate alert-rules user on monitor save
• fix: notify Bugsnag when importing fails
• fix: use alert-rules rules only when enabled
• docs: update maintenance window docs
• fix: only load/dispatch load if we have an ID (#97)

API updates

• feat: maintenance Window feature (#327)
• feat: migrate TCP Port for Classic users (#334)
• feat: enable Webhook channel and Team Management
• fix: send monitor created event after migration