Remove sudo from Moonriver (and Alphanet temporarily)

[JoshOrndorff]

This PR removes pallet sudo from the moonriver runtime. After this PR the only ways to dispatch with root origin will be through democracy or council.

[girazoki]

Remember to remove traces in the Rust integration tests. I see

assert_eq!(
		<moonriver_runtime::Sudo as StorageInfoTrait>::storage_info(),
		vec![StorageInfo {
			prefix: prefix(b"Sudo", b"Key"),
			max_values: Some(1),
			max_size: Some(20),
		}]
	);

In Moonriver integration tests

[crystalin]

@JoshOrndorff we need to set the pallet index in moonbase I believe, can you do that ?

[notlesh]

LGTM, however, there are a lot of changes around the it("should be able to register many accounts - batch : " test that seem unnecessary. Probably not a big deal if we simply intend to git revert this soon.

[girazoki]

Yeah still I know I added a sudo-dependent test yesterday. I used sudo to enact a democracy proposal. Didnt realize about this PR. I can try to change it to make it be approved by regular means, or do you want to do it @JoshOrndorff ?

[crystalin]

Ideally we would want to move those tests to use democracy,
But in short term, we decided to disable them until we restore Sudo on Alphanet (probably in a week)

[JoshOrndorff]

I prepared this one to restore sudo to moonbase. #652

I'll just leave it open until we're ready for it.