afterImageUploaded should ignore query string distinguishing image files

**Description**
I use Firebase Cloud Storage as image storage, which makes public image url be `https://...fileName.png?alt=media`.
When I call `onSuccess` handler after uploading and getting the public url, it inserts the content as normal link (`[title](url)`) while expected to insert as image (``).

This is because easymde calls `afterImageUploaded` function internally when `onSuccess` handler is called. It simply uses the last part of the image url (query string `?alt=media` included), which means any url which has query string will not be handled as image even if it really has the extension of image.

https://github.com/Ionaru/easy-markdown-editor/blob/072176a86ebbd17fabe47845866610e77e65f779/src/js/easymde.js#L810

```javascript
var imageName = url.substr(url.lastIndexOf('/') + 1);
var ext = imageName.substring(imageName.lastIndexOf('.') + 1);

// Check if media is an image
if (['png', 'jpg', 'jpeg', 'gif', 'svg'].includes(ext)) {
_replaceSelection(cm, stat.image, options.insertTexts.uploadedImage, url);
} else {
var text_link = options.insertTexts.link;
text_link[0] = '[' + imageName;
_replaceSelection(cm, stat.link, text_link, url);
}
```

The part getting file extension from url should be like:

```javascript
var ext = url.split(/[#?]/)[0].split('.').pop().trim();
```

I took this example from: https://stackoverflow.com/a/47767860/5359376

**Expected behavior**
`afterImageUploaded` handler should ignore query string in the uploaded image url.
Also, it would be great if these extension or the tag choosing strategy be customizable.

Thank you.

Start in src/js/easymde.js around line 810, where afterImageUploaded derives the extension from the uploaded URL. Reproduce an upload URL containing a query string such as ?alt=media, then verify that the handler inserts image markdown rather than a normal link while preserving existing behavior for URLs without queries.

Written by the indexing model from the issue text.