feat: Add new API notebook

[InertGas01]

> curl -X GET http://127.0.0.163:8000/notebook/User_Guide
Shows the content of note "User_Guide".
"/<Title>/ Show the content of the note with title <Title>."

> curl -X PUT http://127.0.0.163:8000/notebook/new_note_title/content
Create a new note named "new_note_title" with content "content".

> curl -X POST http://127.0.0.163:8000/notebook/new_note_title/Content
Change the content of note "new_note_title" from "content" to "Content".

> curl -X POST http://127.0.0.163:8000/notebook/new_note_title/append/can't
> curl -X POST http://127.0.0.163:8000/notebook/new_note_title/append/contain
> curl -X POST http://127.0.0.163:8000/notebook/new_note_title/append/whitespaces.
Append " can't", " contain", " whitespaces." respectively to the content of note "new_note_title".

> curl -X GET http://127.0.0.163:8000/notebook/new_note_title
Shows the content of note "new_note_title".
"Content can't contain whitespaces."

[andy89923]

Hi @InertGas01 ,

Please use rebase to merge the same commits into one. (eg: fix: linter error) .