Cosmospy

- Added
- `cosmospy.seed_to_privkey` function
- Changed
- `cosmospy.typing.Wallet` now includes fields "seed" and "derivation\_path"
- Made private keys and public keys in all public interfaces type `bytes` instead of hex formatted `str`

- Changed
- `cosmospy.transactions` and `cosmospy.addresses` modules have been removed.
All of their functions and classes are now importable directly from the `cosmospy` root.
That is, users will have to `from cosmospy import Transaction` instead of `from cosmospy.transactions import Transaction`.
- `get_pushable_tx` method of the `Transaction` class renamed as `get_pushable`

- Changed
- `transactions.Transaction` init only takes keyword arguments.
- `transactions.Transaction` keyword argument `chain_id` default value changed from "cosmoshub-2" to "cosmoshub-3"
- Made all instance variables of `transactions.Transaction` private
- Renamed `transactions.Transaction.add_atom_transfer` as `transactions.Transaction.add_transfer`

- Changed
- Renamed `transactions.UnsignedTransaction` as `transactions.Transaction`

- Added
- `addresses.pubkey_to_address()`
- `transactions.UnsignedTransaction` class
- Removed
- `transactions.sign_atom_transfer()`
- `transactions.sign()`

- Added
- Code for address generation and transaction signing