anonymous proxy should add provider

[xlc]

I think we should add provider for anonymous proxy so it can be used by consumers without extra deposit. Alternatively, the reserve should made on the proxy account instead of the creator.

On kill_anonymous, it should try to dec provider and refuse to kill if that failed (due to still have consumers).

Migration will be needed to update existing anonymous proxies (but not sure if that's possible though purely based on on-chain data).

cc @gavofyork

[stale]

Hey, is anyone still working on this? Due to the inactivity this issue has been automatically marked as stale. It will be closed if no further activity occurs. Thank you for your contributions.