Remove references to unused assets and features

[brendo]

What this PR does

This PR is a cleanup to:

1. Remove non-existent references to JS files from the Rails precompile.

    "shopify_app/post_redirect.js",
    "shopify_app/top_level.js",
    "shopify_app/enable_cookies.js",
    "shopify_app/request_storage_access.js",
    "storage_access.svg",
   

2. Remove the storage_access.svg

3. Remove unused translation keys for features that have been removed.

Most of this is related to old features such as cookies (#617), which was removed in #1611 (2 years ago).

Checklist

Before submitting the PR, please consider if any of the following are needed:

• Update CHANGELOG.md if the changes would impact users
• Update README.md, if appropriate.
• Update any relevant pages in /docs, if necessary
• For security fixes, the Disclosure Policy must be followed.

[paulomarg]

Couldn't find any of the files removed here, and ran the gem on an app. Everything LGTM!

Thanks for taking this on!