Update cloud-providers.html

[cnChenKai]

Enable auto register for new account.

[Alkarex]

Hello, Before merging, a couple of details:

• It could be good to enable a Terms of Service, see https://freshrss.github.io/FreshRSS/en/admins/12_User_management.html#enable-terms-of-service-tos
• Not mandatory, but maybe add a bit of background information about this service, so that users get an idea of what is service is. For instance location, type of server, capacity, is it managed by a single person or a group, motivation, etc.

Edit: see https://github.com/FreshRSS/freshrss.org/pull/56#issuecomment-1479505160 for more info

[Alkarex]

https://freshrss.mubibai.com/ seems to be offline? Closing here, but feel free to re-open a PR if relevant (again)