Added Webhooks for Sequenced Optimisations

• Sequenced Optimisation Completed
• Sequenced Optimisation Customer Notified
• Sequenced Optimisation Deleted

Added API Reference for Sequenced Optimisations

• List Sequenced Optimisations
• Lookup Sequenced Optimisation
• Create Sequenced Optimisation
• Trigger Customers Notified
• Terminate Sequenced Optimisation
• Delete Sequenced Optimisation