v1.0.0

Update instructions:

• Remove check_updates option from impulse.yml
• Remove application.message_template option. Instead you can use application.template_files
• Rename webhook.user to webhook.auth

Changes:

• New incident message structure. Contains status_icons, header and body
• Added template files for incident message components
• Changed impulse.yml format
• Fix Mattermost update payload
• New notifications format
• Mattermost buttons state fix
• Update Mattermost button payload
• Fix user_group notifications