Feature: note.rs

[falk-werner]

This PR introduces a new module: note.rs (finally)
There is no new functionality, just moved the current implementation from main to the new module.

[fersaru]

One Note, two notes, all a part of a notebook.
I would like that

[falk-werner]

One Note, two notes, all a part of a notebook. I would like that

I renamed the struct to Notebook, just to show how this would look like.
Note that this would lead also to renaming of some of the APIs, as notebook.list() does not make any sense, since there is only one. It is also very common to use singular in APIs (see swagger's petstore) and also in database tables. (I took a look at swaggerhub and also found quite a number of APIs that uses plural, but it seems to me, that notes would be preferred by them.)

Also note, that I've only applied this change to the backend. When applied to the frontend, it would have impact on note.js, since we plan to share the same frontend in the future.

[fersaru]

I don't like the idea of changing the frontend so it becomes unique to this note.* implementation.
The "interface" should present the same function signatures as the other backend implementations.
But how the function is implemented should be backend specific.

In the current naming I don't like the _ in list_notes because when I think in objects it reads like there should be a notes object.
In objects speaking I thought one notebook has all the configs it needs, it holds a quantity of notes and has the functionalities to present them in a desired format (like a list of only the names). A note would then have knowledge about it's name, it's path and it's tags.

But I think this becomes too complex for the initial idea of having a simple note-tool.
I didn't aim for a discussion about a change in the API with my proposal. I was just thinking "out loud".

I think going back to the "note" naming is closest to the note.* idea, so i would go back to it for now.