ci: move the deploy to a new account and buckets

[rogerlz]

As discussed over Discord, we need to move the S3 buckets hosting https://app.fluidd.xyz and https://dev-app.fluidd.xyz to a new account. I took the opportunity to replace the deprecated tool to upload to S3 with a GitHub action that supports a more modern authentication method.

There are a few secrets to be added to the repository settings, which I will share via private message.

Signed-off-by: Rogerio Goncalves [email protected]