Magento 2 Product Attribute type "File Upload"

We're using Magento CE2.1.7 and need a possibility to add files with attributes. Currently there are the following attribute types ("Catalog Input Type for Store Owner"): Text Field Text Area Date Yes/No Multiple Select Dropdown Price Media Image Fixed Product Tax Visual Swatch Text Swatch We need an additional type "File Upload". With this new type, we should be able to create new attributes which can have files, e.g. "Manual" and "PDF Description", both of them could then be added as attributes to products. We have a working magento extension for this for Magento 1.4, now we need the same for 2.1.7. If that's possible, the old extension can just be rewritten to work with the new version. It's only like 4 or 5 files in the plugin, so it shouldn't be a problem if you're familiar with magento structures. The old extension is added as zip, you can have a look there. You don't need any special data for this plugin to work, you can just setup a local magento installation (done in 10 minute) and then start do develop, attributes can be created without any product or other data. I also added an image of how the file upload attribute looks now in Magento 1.4, it should work exactly the same in Magento 2.1.7. The attribute "filetest" you see is an attribute with type "File Upload" which can be added to products and attribute sets. Attributes are added via Stores -> (Product) Attribute -> Add New Attribute, that's where the file upload should appear in 2.1.7 (see Printscreen). ATTENTION: I don't need someone who just searches the internet for suitable plugins, there are none. I need someone who is familiar with Magento 2 development and who is able to code this by himself - so please only people who are able to do that. Plugins who can also provide functionality with uploading files is not what I need, I need an attribute type File Upload. Please make sure you fully understand what's to do - offers in the first 5 minutes are ignored, please take your time to read and look at everything. Thanks!