[JS Addons] Addon storage class for handling addons related file/folder functions

[krmanik]

Pull Request template

Purpose / Description

Handle addons related file/folder functions in a centralized class AddonStorage.

Fixes

Fixes

Approach

1. Create new class AddonStorage and implement possibly used methods
2. Move methods for addons related file/folder to AddonStorage

How Has This Been Tested?

Implemented unit test

Learning (optional, can help others)

Describe the research stage

Links to blog posts, patterns, libraries or addons used to solve this problem

Checklist

Please, go through these checks before submitting the PR.

• You have not changed whitespace unnecessarily (it makes diffs hard to read)
• You have a descriptive commit message with a short title (first line, max 50 chars).
• Your code follows the style of the project (e.g. never omit braces in if statements)
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings)
• UI Changes: You have tested your change using the Google Accessibility Scanner

[david-allison]

Great!

As this is a refactoring, let me know if you want to move these comment to follow-ups

[mikehardy]

@david-allison I think this one is on you for a re-look?

[david-allison]

I don't feel my comments from the previous round have been addressed

[krmanik]

I will update the PR later.

[github-actions]

Hello 👋, this PR has been opened for more than 2 months with no activity on it. If you think this is a mistake please comment and ping a maintainer to get this merged ASAP! Thanks for contributing! You have 7 days until this gets closed automatically

[mikehardy]

Pinning this open - it will happen...

[krmanik]

The addons feature is in progress. I have created a discussion on https://forums.ankiweb.net for better cross platform addons support.
https://forums.ankiweb.net/t/ideas-features-cross-platform-js-addons-support-using-rust-backend-and-svelte-frontend/21172?u=krmanik

Also to learn/understand more about backend and addons support, I started creating feature for Anki which will be available to Anki Ecosystem.
krmanik/anki#1