Asset Exchange: Fabric with Besu

We will demonstrate asset exchange of a bond in Fabric network1 with 10 BobERC20 tokens on Besu network2. For Fabric commands, run from samples/fabric/fabric-cli folder, and for Besu commands, run from samples/besu/besu-cli folder, in your clone of the Weaver repository. Here Alice and Bob in Fabric network1 correspond to account 1 and account 2 in Besu network2 respectively. Following are the step-by-step asset exchange process:

Notes
The hash used in following steps can be replaced by any valid `SHA256` hash.

From fabric-cli, generate secret-hash pair using following command (prints hash in base64):
```
./bin/fabric-cli hash --hash_fn=SHA256 secrettext
```
Run the following to verify the status of the bond assets owned by alice and bob in the Fabric network network1 from samples/fabric/fabric-cli folder:
```
./scripts/getAssetStatus.sh
```

Run the following in besu-cli, to verify the status of the assets owned by Alice and Bob in the Besu network network2:

./bin/besu-cli asset get-balance --network=network2 --account=1
./bin/besu-cli asset get-balance --network=network2 --account=2

Run the following to trigger alice locking bond01:a03 for bob in network1 for 60 mins:

./bin/fabric-cli asset exchange lock --timeout-duration=3600 --locker=alice --recipient=bob --hashBase64=ivHErp1x4bJDKuRo6L5bApO/DdoyD/dG0mAZrzLZEIs= --target-network=network1 --param=bond01:a03

Run the following to verify alice's lock:

./bin/fabric-cli asset exchange is-locked --locker=alice --recipient=bob --target-network=network1 --param=bond01:a03

Run the following to trigger bob locking 10 units of BobERC20 tokens for alice in network2 for 30 mins:
```
./bin/besu-cli asset lock --network=network2 --sender_account=2 --recipient_account=1 --amount=10 --timeout=1800 --hash_base64=ivHErp1x4bJDKuRo6L5bApO/DdoyD/dG0mAZrzLZEIs=
```
Note the contract-id printed as output in above command. The output line containing contract-id (text in base64 after Lock contract ID:) would like this:
```
Lock contract ID: 48f59da2ac632117bf79b4aa986f5ece8a2439dc143d576965c17bc8275b0925
```
Let's refer it <contract-id-2> for this demonstration.

Run the following to verify bob's lock:

./bin/besu-cli asset is-locked --network=network2 --lock_contract_id=<contract-id-2>

Run the following to trigger alice's claim for 10 units of BobERC20 tokens locked by bob in network2:

./bin/besu-cli asset claim --network=network2 --recipient_account=1 --preimage=secrettext --lock_contract_id=<contract-id-2>

Run the following to trigger bob's claim for bond01:a03 locked by alice in network1:

./bin/fabric-cli asset exchange claim --recipient=bob --locker=alice --target-network=network1 --param=bond01:a03 --secret=secrettext

Run the following to verify the status of the bond assets owned by alice and bob in the Fabric network network1 from samples/fabric/fabric-cli folder:
```
./scripts/getAssetStatus.sh
```

Run the following in besu-cli, to verify the status of the assets owned by Alice and Bob in the Besu network network2:

./bin/besu-cli asset get-balance --network=network2 --account=1
./bin/besu-cli asset get-balance --network=network2 --account=2

The above steps complete a successful asset exchange between Fabric and Corda networks. In addition to the above commands, following commands can be run if specified timeout has expired and the locked asset remains unclaimed.

If alice wants to unlock the bond asset, run the following to trigger alice's re-claim for bond01:a03 locked in network1:
```
./bin/fabric-cli asset exchange unlock --locker=alice --recipient=bob --target-network=network1 --param=bond01:a03
```
If bob wants to unlock the token asset, run the following to trigger bob's re-claim for 50 BobERC20 tokens locked in network2:
```
./bin/besu-cli asset unlock --network=network2 --lock_contract_id=<contract-id-2> --sender_account=2
```