Automatically upload images when paste about cowyo

[hurui200320]

I found the following resources on paste images:

https://stackoverflow.com/questions/59769305/how-to-paste-files-into-an-input-using-ctrl-v-paste
https://webdevchallenges.com/how-to-paste-files-from-clipboard-using-javascript

However, I didn't find where I can integrate into cowyo yet...

[hurui200320]

Seems like we can accept onPaste event here?

cowyo/templates/index.tmpl

Lines 155 to 159 in a58f4ca

	<textarea
	autofocus
	placeholder="Use markdown to write your note! New: you can publish your note when you are done ({{ .Page }} -> Publish)."
	id="userInput"
	>{{ .RawPage }}</textarea>