Feat add benchmarks payments

[darkforest0202]

This PR adds the benchmarking for all the extrinsics defined in the pallet.

Here the successful test executions:

➜  virto-node git:(feat-add-benchmarks-payments)  cargo test --package pallet-payments --features runtime-benchmarks
    Blocking waiting for file lock on package cache
    Blocking waiting for file lock on build directory
   Compiling pallet-payments v0.1.0 (/Users/hectorb/side/dark/virto-node/pallets/payments)
    Finished test [unoptimized] target(s) in 7.70s
     Running unittests src/lib.rs (target/debug/deps/pallet_payments-f80d3ba3c5e8ade5)

running 8 tests
test tests::payment_refunded_request ... ok
test tests::request_payment ... ok
test mock::__construct_runtime_integrity_test::runtime_integrity_tests ... ok
test tests::test_pay_and_cancel_works ... ok
test tests::test_pay_and_release_works ... ok
test tests::payment_disputed_sender_wins ... ok
test tests::payment_disputed_beneficiary_wins ... ok
test benchmarking::benchmarks::benchmark_tests::test_benchmarks ... ok

test result: ok. 8 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.03s

   Doc-tests pallet-payments

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

Please note that benchmarks cannot be executed until the task #309 is not completed.