FedStats Quantile and Tutorials Update

[chesterxgchen]

FedStats Quantile metrics

• Replace t-digest python package ( which require python3-dev dependency) with fastdigest ( which requires cargo rust dependency). Make the installation of fastdigest optional
• move make the quantile optional, only available when fastquantile is installed.

Tutorial 2nd Pass Update

1. Chapter 1 -- introduction to logging section
2. Chapter 2 -- Update
   • Chapter 2.1 -- Expand the fed statistics with background and explanation
   • Chapter 2.2 -- Expand the Client API section with additional figure and details tutorials
   • Chapter 2.3 -- re-organized the section make client API goes first. Add a lot details for logistics regression, removed the Job API code, As it doesn't work right now.
   • Chapter 2.5 --recap, re-write the summary to avoid it as the repeat of the introduction
3. Chapter 1-2-3 grammar check update

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).
• Breaking change (fix or new feature that would cause existing functionality to change).
• New tests added to cover the changes.
• Quick tests passed locally by running ./runtest.sh.
• In-line docstrings updated.
• Documentation updated.

[chesterxgchen]

/build

[chesterxgchen]

/build

[chesterxgchen]

/build

[YuanTingHsieh]

folder inside Chapter 2.4 should be 2.4.xx

[chesterxgchen]

/build

[chesterxgchen]

/build