POC for MP multi-file uploader to S3

[mantasmuliar]

Overview

POC for Marketplace multi-file uploader.
The functionality is fully working with usage examples both for generic media file, and CSV import file uploads.

Implementation relies on Service/AwsS3 module for communication with AWS api.
Remaining modules in ZED provides internal functionality:

• FileUpload - generic entity manager (CRUD) module for persisting uploaded files metadata in the database.
• FileUploadMerchantPortalGui - provides API endpoints for Angular file uploader calls and GUI for listing merchant's uploaded files.
• MerchantProductImport - entity manager module for handling uploaded import file's progress tracking.
• MerchantProductImportMerchantPortalGui - provides GUI for tracking merchant product import files processing progress.

Usage example in frontend:

{% embed 'ZedUi/Partials/file-upload.twig' with {
    data: {
        errorType: 'Only image/png, image/jpeg file formats are allowed' | trans,
        multiple: true,
        fileData: [
            {
                size: 2,
                errorSize: 'The file should be less then 2MB' | trans,
                types: ['image/png', 'image/jpeg'],
            },
        ],
    }
} %}
    {% block textData %}
        <ul description>
            <li>
                {{ 'You can upload multiple images' | trans }}
                {{ 'Max allowed single image size - 2MB' | trans }}
            </li>
        </ul>
        <span modal-title>{{ 'Import Images' | trans }}</span>
        <span input-label>{{ 'Choose or drag your images' | trans }}</span>
        {{ 'Import Images' | trans }}
    {% endblock %}
{% endembed %}

[matweew]

so my general feedback for this PR is following:

• modules code has to be moved under Spryker\ namespace to spryker/spryker repository
• AWS S3 functionality can be used via the existing module spryker/file-system and adapter for S3 from spryker/flysystem-aws3v3-file-system or the adapter can be updated for this story needs.
• (optional) FileUpload can be replaced with spryker/file-manager
• MerchantProductImport is renamed to MerchantProductUploader
• Functional tests are added for main modules (not GUI)
• The modules have to be released as beta 0.1.0, so we will have opportunity to change API & DB structure later before 1.0.0.