simple upload adapter flexibility

[kartsims]

I was trying to add a bit of flexibility to the simple upload adapter in order to be able to upload directly to our CDN provider (upload care CDN).

Two things were needed:

• add our public key as a form data (alongside the uploaded file)
• transform the response which is just a UUID to fit the expected format { default: <imageURL> }

I don't know if this falls in the scope of this add-on but I find it convenient to use this way. Feel free to close this PR and suggest to split those changes in two PRs if need be.

[Reinmar]

HI! Thanks for the PR.

Both use cases make sense – being able to append more data to the request and process the response. The implementation looks good as well. So, conceptually, I think this would be a great addition.

To merge this PR we'd need:

• tests
• code style fixes
• signed CLA

Let us know if you want to give those a try and if you have any problems with them.