refactor: Implement account_id_to_shard_id as a method in ShardLayout

[wacban]

Description

Today we use a function called account_id_to_shard_id in order to figure out what shard an account belongs to. It's a bit annoying to use. A better way would be to have it as a method in ShardLayout. This would be nicer since then the IDE can suggest this method when dealing with ShardLayout. It also seem more natural to have it as a method.

The goals of this issue are to:

• Implement account_id_to_shard_id as a method in ShardLayout
• Adjust the existing account_id_to_shard_id to simply called the ShardLayout::account_id_to_shard_id
• Migrate a few usages of the old one to the new one.

There is no need to migrate all of the old usages as that may be annoying and of little learning value. It's fine to just do a few to show that it works.

reference:

nearcore/core/primitives/src/shard_layout.rs

Lines 760 to 765 in 10369c6

	/// Maps an account to the shard that it belongs to given a shard_layout
	/// For V0, maps according to hash of account id
	/// For V1 and V2, accounts are divided to ranges, each range of account is mapped to a shard.
	///
	/// TODO(wacban) This would be nicer as a method in ShardLayout
	pub fn account_id_to_shard_id(account_id: &AccountId, shard_layout: &ShardLayout) -> ShardId {

[virajbhartiya]

Can I work on this?

[wacban]

@virajbhartiya Sorry, it's a ramp up task for someone else.