feat: add manual initial storage slots

[MujkicA]

Closes #86

This PR enables manual initialization of storage slots via the SDK. deploy and deploy_with_salt() now accept a Vec<StorageSlot> which is used to calculate the contract_id on the SDK side and forwarded via the contract deployment transaction.

I have discussed multiple options for the UI with @digorithm. The conclusion is that the above approach creates the least amount of cognitive load for the user, i.e. they don't have to remember another workflow.

let storage_slot = ...

let contract_id = Contract::deploy(
        "tests/test_projects/storage/out/debug/storage.bin",
        &wallet,
        TxParameters::default(),
        vec![storage_slot.clone()], // <----------
    )
    .await?;

Since StorageSlot requires the user to convert key/value to Bytes32 I thought it would be convenient to provide a helper to create a slot from a generic key-value pair.
create_storage_slot uses unsafe Rust and panics if key/value is larger than 32 byte since this is their limit as stated in the specs.

let storage_slot = create_storage_slot("slot", 42);

[iqdecay]

Use already existing functions for storage slots, and make the storage slot vec non mandatory for vanilla deployment

[iqdecay]

I think you removed too many things
EDIT: thought I had received a review request, mb sry

[iqdecay]

I think you removed a commit by mistake

[MujkicA]

After some changes the test in examples turned out to be the same as the one in harness. I moved the ANCHOR tags to harness and removed the example.

[digorithm]

LGTM, nice work on the API!

[iqdecay]