Rename package to `@hedera/sdk`

[janaakhterov]

Problem

Currently the package name is @hashgraph/sdk, but the name doesn't make all that much sense because this isn't an SDK for the Hashgraph algorithm, this is an SDK for Hedera Services which are built on top of the Hashgraph algorithm.

Solution

Try to acquire @hedera on npmjs.org and release the SDK as @hedera/sdk, @hedera/cryptography, @hedera/proto. Perhaps this could be done for v3 whenever that happens?

Alternatives

No response