refactor(test): move tx test utils to testenv

refactor(test): move tx test utils to testenv

- add `utils` mod to testenv crate to keep all
utilities moved from `crates/chain/test/common`
- replace all test tx macros in `chain` crate with
import from `testenv` crate
    - tests/test_indexed_tx_graph
    - tests/test_keychain_txout_index
    - tests/test_local_chain
    - tests/test_tx_graph
    - tests/test_tx_graph_conflicts
- deleted all moved macros and functions in
`crates/chain/test/common/mod`
- replace `bitcoin` external crate with
`bd_chain::bitcoin`
- move `DESCRIPTORS` sample array to `utils` for
other crates to use
- rename h! macro to hash! for clarity
- rename localchain! macro parameter from
'block_hash' to 'hash'

[Ticket: #1602]