Add the optimization example for ServerlessToDoListAPI

[zhululai]

• [x] Ensure that the commit message is a good commit message
• [x] Ensure to use auto format in all files

---

Short Description

This pull request aims to add the optimization example for ServerlessToDoListAPI.

Resolving Issue / Feature

This example contains the performace specification of ServerlessToDoListAPI, which is needed by the decomposition tool to carry out deployment optimization. In particular, service templates with different reference workloads and Python utilities for benchmarking and load testing are included. A few minor issues were also fixed when the upstream was merged into the fork.

[zhululai]

Looks basically good, however ... what have you changed in the artifact files of the ServerlessToDoListAPI blueprint? Why do we need to update them?

I did a load test on ServerlessToDoListAPI and found some bugs in the original implemenation. For example, the get-item function can't correctly check if an item exisits or not. Also, the update-item function creates a new item when the item to be updated doesn't exist. I modified the function packages to solve these bugs.

[miwurster]

I did a squash-merge... Remember to reset your own branch to the laster master.