Feat (NoteService): Implement getNoteTitle() method

## Story
In some cases frontend part needs just note title to display iniformation about note
e. g. in home page we can see only `noteTitles` of the each note, for that case we do not need to pass whole `noteContent` as we do, we could just pass `noteTitles`

You can check reference of the method in [notes.web](https://github.com/codex-team/notes.web) repo

## Problem
In some cases we do not need whole note content, but we need note title which can be formed only in web part

## Steps
- Add `getNoteTitle()` method for `NoteService`
- Add `NoteTitle` and (`NotePreview` or `NoteMeta`) entities
`NoteTitle` is string
`NoteMeta` is actual note, with NoteTitle instead of content
- Check, where we use `getNoteTitle()` method on the WEB part